Unless you are willing to buy an obsolete (like Core2 Duo obsolete) laptop, expect to spend at least a grand. Unless I am mistaken, the cheapest Apple laptop is the base 11 inch Macbook Air.
http
/store.apple.com/us/buy-mac/macbook-air They are basically the same price anywhere so you might as well get it straight from Apple's site or an Apple store unless you want to try it first and you don't have a nearby Apple store. Even used i5 and i7 Sandy Bridge Macbooks are still selling for more than $600. although you might find one are two in rough condition like cracked screen or dented body or with bad batteries for that price or less.