Originally Posted by Falcon16
I'd say personally just build a box that's big enough. I find a great way to do it is to use just cheap plywood for the for the bottom and sides. then buy a good quality white sheet and stretch it out over the frame so there are no wrinkles then tak it in place on the table you'll have the box sitting on with pushpins or simply weight it with something heavy so it'll stay taught. Reason i'd say go for this approach vs a built lightbox is 1) it's cheaper and 2) you could buy multiple sheets and customize the box for the particular product you're shooting not to mention if the sheets get dirty for whatever reason you just bleach them and they're back to perfect white again easily.
This. I use a homeade "lightbox" as well (though its more triangular shaped, and not constructed very well... really, its just enough to get by as a seller of used goods who doesn't care all THAT much) and the great thing about it is that I never feel bad about having to change the setup or playing with it more to get it just right for what I need. I think Falcon's description is spot on for somewhere to start.