Go playing sets vary widely in quality. You can get beginner sets under £10, a full-size set with glass stones and wooden board for under £50 or you can spend £1,000 or more. Some sets have mat or wooden boards of various sizes (9, 13 or 19 lines) and plastic or glass stones. There are also magnetic sets for use when travelling.
Don't forget if you're a novice that it is best to start playing on smaller boards before moving up to the large 19x19 one. Some boards have a different size version on the reverse, helping you through this progression without the expense of buying another board.
As an alternative to purchasing a set you could make your own. Making stones can be a difficult, so we'd definitely recommend buying them; printing your own 9x9 or 13x13 board is much easier. You might want to look at the board of the BGA-designed A3 laminated BGA Takeaway Go Set.
Note on Buying Boards and StonesIf buying stones and boards from differing sources, be careful to check sizes as some slightly larger Chinese stones do not quite fit onto the Japanese-standard boards which are the norm in the UK.
There are a number of UK retailers of sets and books, including good games shops you can visit.
There are various non-UK suppliers that ship to the UK. Note that since Brexit, some suppliers listed no longer ship to the UK. The list includes publishers, shops and mail order companies.
The most useful of these were Go Shop Keima, the online branch of the Het Paard shop in Amsterdam. We understand that Hebsacker Verlag in Germany will, post-Brexit, no longer ship to the UK, but this might of course change in the future.
See our Education Section