Where to Buy

Note that this guide is geared mainly towards UK-based succulent enthusiasts. I used my personal experiences as well as info gathered from this Reddit thread to make this guide.

Supermarkets & DIY/Home Improvement Stores

You can usually find succulents at Tesco, Asda, Lidl, IKEA, and B&Q. These stores will usually have stuff like some common echeveria and fenestrated haworthia; haworthia pumila and attenuata; common sansevieria; aloe vera and aristata; common / random cacti; kalanchoe blossfeldiana; maybe some jades; and seasonal succulents like hoya kerrii around Valentine's Day, and schlumbergera truncata around Christmas time. Lidl in particular usually has some in stock every few weeks, and stocks loads of schlumbergera around Christmas. IKEA also seems to have a decent selection.

You may occasionally find slightly less common stuff like peperomia and kalanchoe tomentosa, but this may vary depending on where you are. I've found a gollum jade and opuntia microdasys at my local B&Q, but I've heard others say that their local branch never has anything decent in. Another time, someone was posting about a great selection at their local Lidl that week, whereas mine only had like two jades. Regardless of where you are, however, you're highly unlikely to see anything really interesting. I've never seen a lithops in any of those stores, for instance.

Plants from these stores usually come in terrible potting mix, so it's a good idea to repot with your preferred soil mix once you get them home. They can also be stupidly overpriced sometimes, as they may come in nice pots which make up the majority of the sale price. Tesco in particular is on my bad list for selling tiny succulents for £4-5, for which most of the price was attributed to these crappy magnetic pots that I didn't even like!

Surreal Succulents

I like their online store, but they only really have a good selection of aeonium, echeveria, and sempervivum, as well as some of their own original hybrids. They don't sell any kind of cactus. They will usually have some common plants like jade and string of pearls, but I've found that these tend to sell out fairly quickly, and it can take a while for them to get back in stock. If you want sedum, haworthia, cacti or rarer succulents, you'll have to go elsewhere.

Cactus Shop

I like their online shop too. They have a large variety of succulents, but you still won't find everything there. They don't have lithops (why?!). The nursery itself is based in Winkleigh, Devon. I've heard that it's really worth visiting if you're ever in the area.

Cactus Plaza

Based in the Netherlands. These guys have a pretty large selection of succulents, with a good mix of common and rarer plants. Their prices are pretty good too, but shipping to the UK is expensive, at €14.50 (£12). It's not worth it at those prices, unless you're purchasing in large quantities, or buying an extremely rare plant. It'd probably be better to get your plants elsewhere.

Prick

A cactus boutique in London. I don't know what their in-store selection is like. They have an online store but the selection is very limited and is, in my opinion, a bit overpriced. However, their shipping prices are really good. Seriously.

Update (22/03/2018): Prick has increased their shipping prices; 2nd class delivery is now over £3 as at this update.

It might be a good idea to visit the store in person if you're in London, as it seems like a cool place.

Ralph Martin

Private collector with a small-ish collection. He also does swaps/trades, if you have anything on his wish list. I got three plants from him – one I wasn't super happy with as it looked like a few of the leaves had been eaten by slugs, but the other two were in very good condition.

Abbey Brook Cactus Nursery

A highly reputable nursery in Matlock, Derby; it's listed on the BCSS site. The problem is that it's far out for most people, has a narrow window for their opening hours and they don't sell online. But if you're in the area and they're open, it's definitely worth stopping by. They have a large variety of plants they grow themselves, including many kinds of cactus and other succulents, and a huge variety of lithops, my favourite! I finally managed to visit them, and definitely recommend visiting if you're in the area.

Tony Irons Cactus Nursery

Based just outside Bristol, this guy is also listed on the BCSS site. I first heard of him from a Cactus Mall list of all UK succulent nurseries. That site is almost useless; half of the links are broken. The link to his website worked, but he doesn't sell on there anymore. Seems that it might be worth checking out if you're in the area. He also has an eBay shop (see below).

BCSS Events

The British Cactus and Succulent Society hold many events around the UK each year that are open to any and everyone. You can buy directly from experts who can give you bespoke care advice, and you're bound to find rare and coveted species grown by enthusiasts like yourself.

/r/succulents

It's a good idea to post on, and scour, the monthly trade threads on this subreddit to see if any UK/EU redditors have anything you want. I've had nothing but good experiences with the people on this sub.

Just Seed

I originally found these guys on eBay, but I found out later they have a separate website; I got my mixed lithops and myrtillocactus geometrizans seeds from them. They only have a tiny variety of cactus and mesemb seeds, so they're great for beginners who want to be assured that they're getting genuine seeds. If you're looking for something rare or specific, you won't find it here!

eBay

You can buy from sellers on eBay, but you just have to be aware of the risks and be extra careful. I bought my fukurokuryuzinboku and my lithops optica rubra on eBay, so it can definitely be done.

Here are some things to do when considering buying from an eBay seller you haven't used before:

Check what else they're selling. If they're selling lots of random stuff with only a few succulents, it's probably best to steer clear and go with a seller who specialises in succulents and knows what they're doing.
Read through their negative reviews and read through feedback to see if anyone has complained about receiving the wrong plants or dead/rotting plants. Also look through the seller's responses to negative feedback to see how they act when there is an issue with an order.
Look through their positive reviews to see whether the customers who are happy with the seller include any who have purchased succulents.
Thoroughly inspect the display pictures on the listing for visible bugs, disease and rot.
Be aware that many sellers will use stock photos which they've taken from Google, rather than taking their own pictures of the actual plant they're selling. This makes some sense for seed listings, and for bigger vendors who have large quantities of stock. However, I still personally prefer vendors who use pictures of their own stock as it shows they put some care and thought into their listing and are more likely to know what they're doing.
Similarly, watch out for listings with a lot of 'buzz words' in the title, like this one. Many of them are Chinese seed listings (see last bullet point).
Make sure that the display pictures correspond with the plant/seed in the listing title and description.
Always always always check the listing description to confirm the size and/or number of the plants/seeds that would be sent to you in an order of 1 unit. If in doubt, contact the seller and ask.
Be extra careful of sellers based in China. Many of these listings are scams; they send you weed/grass seeds or a completely different plant. As a rule of thumb, I personally never buy succulents from Chinese sellers on eBay; I've seen too many selling weeds instead of the advertised plants. I've even seen a few sellers who claimed to be based in the UK but were actually in China. This is another good reason to check the negative reviews!

Here's a list of eBay sellers I've personally had success with:

Just Seed (UK): See above

Floricoltura Lampugnani (Italy): Got my fukuroku from here. They've got a decent amount of rare cacti here. Shipping is expensive, though.

Old-n-Bald (UK): Got a mix of rare lithops seeds from him. He doesn't always have items for sale, but when he does it's most likely gonna be something good.

Cactus Culture (Germany): Got my optica rubra from here. They've got a wide range of stuff.

Here's a list of eBay sellers I haven't personally tried yet but have my eye on:

Paula's Plants (UK): Seems to be of decent quality, but a bit on the expensive side. Sells lots of different plants, not just succulents. Also listed on Cactus Mall.