Assuming you already have a camera, computer, etc. And hopefully you'll already have some lights because that's not a big budget. For a simple white background you could use the savage paper kit. It comes with a small roll of white and the stands you would need. You should probably get one of the wider rolls as well just in case you need a wider shot. Savage Paper Kit
If you don't have lights you'll have to get creative for that budget. Either search for crazy deals on decent lights in the classifieds or maybe use cheap work lights shot into reflectors and through diffusers. Get some black wrap to keep the light from going everywhere.