can i buy Mac OS X v10.7 Lion and install it on a pc?
Basically, no. Anyone who says you can has only created a proof-of-concept and not a workable system because there are no Mac OS X drivers for the computer's hardware.
There are netbooks that run Mac OS X on the market. Google is your friend here. I'm not sure that they're legal given Apple's EULA, and I'm not sure why you'd want to run a Mac on a system it wasn't designed for. Performance is unlikely to be good.
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