Cheap hour building ? I think not !!
Hour building on a Cessna 152 is going to cost about £ 90-100 per hour once all the costs are taken into account, of you go to the USA the aircraft rental is cheap but the costs of airline tickets, hotels, eating out Etc are the things that push up the price to European levels for aircraft rental.
It is a myth that you can fly all day in the USA without encountering weather problems, high winds in Florida afternoons, haze in the LA area & thunderstorms in the mid west are all common problems that stop VFR flight. Now this is were the small print in some hours building contracts gets you, you suddenly find that you can't get the money back if you don't do the contracted hours.
I am not saying that going to the USA is a bad idea but you must go in with your eyes wide open otherwise you are likely to pay more than you expected.
If you do go to the USA stay away from the usual suspects along the east & west coasts, try the mid west or the Michigan as the costs are a lot lower than Florida & California for both the aircraft & accommodation.
The one thing is sure there is no such thing as cheap in this business, the thing to look for is inexpensive, this usually is delivered by a reputable company that at first might look to cost more than the bargain basement operators.