RE material, I would use poster board. For my smaller objects, I use a set up that has a piece of poster board on the bottom and two pieces of foam board that form a right angle for the background. For the clothing, I model them in front of a white muslin bed sheet. In my opinion, you can tell a huge difference because the light doesn't bounce off the muslin as well as the post/foam board.
Example:
http://www.etsy.com/listing/94499792/retro-mugs-set-of-5-w-horizontal-stripesvs.
http://www.etsy.com/listing/94479873/vintage-wiggle-dress-black-w-ruffles?ref=v1_other_2The background in the second listing is dull. Wish I could find a poster board big enough to cover the wall, lol.
EDIT: Looking at them side by side like this, I guess it's not that different. But the editing process for the muslin backdrop is tiring because I have to smooth most of it manually because I don't want it to have that linen texture in the final photo.
Ugh. I wish vinyl backdrops were cheaper!