You could set up subdomains on it. What about these?
car.buy.info - tips on buyingcars
home.buy.info - tips on buying homes
computers.buy.info - tips on buying computers
Then, on the buy.info site, you could list the links to the subdomains so people could click to find that information.
The site could be huge, but would need a lot of information to be worthwhile.
Hope this helps! Good luck!
