It is possible to buy a C or A aircraft use it and then sell it to keep the costs down, a mate of mine did this when building hours for the ATPL but he was a licenced engineer and could ward off most of the pitfalls of aircraft ownership.
The other option is the hours building packages that are avalable but this is also fraught with problems and programs that are used to get you to fly the hours that company's cant sell to anyone else.
The very worst of these programs goes by the very grand title of "structured hours building" in this the company offer you a not very good rate on the aircraft and one of their instructors telling you were to fly to, but this is only good for off peak flying and has a lot of other restrictions that are likely to get your booking bumped if they can sell the slot to someone else. They seem to sell this package to the young and unwise on the grounds that this "structure" has some added value but as you never venture more than an hour or two from base I can't see that in terms of flying experience and of course an hour in the log book is the same be it "structured" or not!
There are some people who will lease you private aircraft to subsidize there own flying, this is OK as long as the aircraft has not been owner maintained. You need to assure yourself that the aircraft is maintained solely by a Subpart F company and not the owner. Also most owners don't like to rent out nice aircraft so you would probably be renting a dog that has over the last few years had as little money spent on it as possible.
Some clubs do offer hours building packages, SFC at stapleford are one who will cut you a good deal but it is a bit restrictive but a lot less so than the so called structured hour building program that is offered by another provider.
The Britsh army always stress in officer training that time spent on reconacence is seldom wasted, I would advise you to take the armys advice and spend a few hours on the Internet searching the options for hour building looking not only at the providers websites but also at blogs from those who have traveled this path before.