If you are just building time, then buying a plane is not the way to do it. It is way too much hassle - as you need to register it, maintain it etc etc.
Personally I would consider joining a syndicate that is already in existance. So you get the benefit of lower cost flying, without the hassle.
You may hit lucky and get a no capital group - where you only have to pay a small joining fee and a low monthly cost.
Unless you are planning on stringing your hour building over a few years, then I don't think setting up a group is going to be worth it. A friend of mine is a founding member of a group - and there is an awful lot of paperwork from what I have seen!
There is also the issue of selling your share - there may not be a willing buyer, and your money may still be tied up in the plane waiting for a buyer.