This is a really, really good time to stock up on game club credits. £2.69 is a bargain price for most of the games on there.
BFG Membership is free and there are no mandatory payments or contracts. Thus, you can sign up now, grab a handful of credits, and immediately "cancel" your membership - this will stop the monthly game club credit purchase coming out automatically but won't stop you using the credits you already bought.
So in a nutshell:
1, Sign up
2, Bulk buy cheap credits
3, Cancel recurring membership (if it forces you to set it up, which I am not sure it does)
4, Use credits any time in the future on games that are normally £5-£7
I'd also like to add for anyone on the fence, I've found BFG to be one of the friendliest, most polite bunch of people ever. Just the other day I made a suggestion to improve their game client, and they gave me a game credit for my effort. They're pretty awesome.