Joining a good group will transform your flying. The magazine articles will tell you the pitfalls to watch out for, but the typical figures quoted can be easily beaten if the group is based on a PFA aircraft. The major disadvantage of this is that no IFR flights are allowed.
I joined a well run group with a two-seat Jodel about three years ago. The share cost £1800 then and has risen by more than inflation. We pay £28 per member per month for all the fixed costs, and £9 per airbourne hour "dry". i.e. we buy our own AVGAS at 18 litres per hour.
The group is so well run that we have just been able to have the engine zero-timed. Not bad eh?
An alternative (again a PFA senario) if you can afford £5k to £7k is to buy yourself a single seater, e.g. Jodel D9 or Turb D31, which you should be able to fly for peanuts. You will have to find some hangarage, but the a/c will probably be a better investment that current b/soc rates!
Final note: When we interview prospective members of our group it is attitude rather than hours that we look for. We often have members who join with a lot less than 100 hours, and we even had a student in the group once. However, we do insist on a proper tailwheel conversion course for new members until the instructor is happy. I can't recall anyone taking longer than five hours for this and some (with previous tailwheel experience) have been "signed-off" in an hour.