For Minecraft on lower settings, $500 should be an OK budget Just look where you want to purchase the thing for either an AMD A8 or A10 system or one with the NVidia 840m/940m video card. For your budget Acer is probably the only brand you would be able to get unless you look for a used system.
Very likely it won't have a 17" screen for that price but will have way more than 100 gig of hard drive space.