I'm with Mono on this.
I used to own 1/10th a share of a Luton Minor based at Shoreham. The share cost £500 and the monthly was somewhere in the region of £25 (memory fails me a bit on that one but it was around that figure). The group has disbanded but the principal is sound. Get a few like minded souls together (if you can find them), decide on type and start a group. Better if you can buy into an established group I guess or even consider outright ownership. I have a Slingsby T31m that is very nearly ready to fly. It's purchase as a glider and conversion costs will amount to around £2000, and I will fly from my farm strip. Flying costs will be around 3 galls/hour of mogas plus a bit of oil. Fixed costs are likely to be fairly low as I'm luckily in a position to have my own strip/hangar and as it will be self maintained, costs there are just delt with on an as and when basis. Insurance is the biggest pain in the butt for me, but I'm hoping to insure through a French company which "may" only cost around £100/yr. This is just to illustrate that it can be done cheaply. OK you may not want to build, but Lutons, VP's, Taylor Mono's ect can be had from as little as £2500. Some, such as FRED's can be folded or dismantled and kept at home in a garage. They may not be sexy, but they get your bum off the ground, are fun, and can keep your licence current. Microlights are similar, and whilst I don't want to put you off them, you can't keep your licence up with one. Also, with the exeption of some older types like early Thrusters, MW7's ect, they also tend to be a lot more expensive than single seat PFA types.
If you want cheap flying ... it is out there, you just have to look beyond the club hangar.
SS