Now
here's a subject I know more about than perhaps I should.

There are three main types of personal lubricant: oil-based, water-based and silicone-based. You can get these from Boots, many supermarkets, Ann Summers, and my own personal favourite - LoveHoney.
Water-based lubes are the most common type, and include such brands as KY Jelly. They contain mostly water along with a few ingredients to make them into a gel. They're suitable for use with most toys and condoms, however they do tend to dry out and become sticky. If this happens, you can just apply a bit more. They're safe for use with pretty much all toys and condoms. Boots (and plenty of other places) do generic versions that work as well as KY but are cheaper. Look in the family planning section.
Silicone lubes last longer than water-based lubes and don't dry out as easily. They're based on silicone and some other ingredients and they don't generally contain water. Some of them are safe for use with toys or condoms, but some aren't because their formulation may interfere with the surface of the device, making it porous or sticky. It's best to check with both the manufacturer of the lube, and the manufacturer of the device you're using, before using a silicone-based lube.
Oil-based lubes are generally stuff like Vaseline or Baby Oil. They are not recommended for use with toys or condoms because they can damage the surface and can even make condoms porous. Oil-based lubes are really only suitable for situations where you won't be using toys or condoms.
There are other types of lubes out there too, such as ones that are specifically formulated for anal use; or ones with anti-bacterial properties; or ones that give you a bit of a tingle. But as a rule of thumb: if you're using toys or condoms, stick to a simple, water-based lube like KY Jelly (or a generic equivalent) and you'll be fine. Just remember to reapply it as required.
As for condoms? It can be a good idea to use these with toys just as a way to keep them clean, particularly if you're using them for anal. The type you buy depends on your preference (and on whether anyone has any allergies to latex). It's also a good idea to buy some anti-microbial toy cleaner to keep everything nice & germ-free. Ann Summers sells Buzz Fresh as handy wipes in individual sachets, or as a spray in a bottle (both of which are pretty good), and Love Honey has a range of excellent toy cleaners too.