Does anyone have any ideas for some homemade photography backgrounds for an indoor studio?

You can make your own from plain white king-sized bed sheets. You can dye them at home.... remember tie-dyed t-shirts?
Just start with the best quality, thickest sheets you can afford.

background stands off eBay

If your looking for canvas or muslin to paint, try your local fabric shop. Even if they dont have something the width you want, they can usually order it, and it'll be cheaper than .

If your looking for something a little different, try your local home improvement center.

In the roofing area, there are rolls of felt, roofing material, panels of lightweight foam insulation, different styles of metal roofing, etc...

There are also different types of expanded metal sheeting, fencing, tiles, indoor/outdoor carpeting, wood flooring, etc...

The garden area is good for fencing, props, scenery, etc....

Plumbing and electrical is good for long pieces of poles (conduit & pvc pipes) for improvised framing.

Dont forget the occasional sales of 2 tube flourescent lights, with 5600K tubes, and round reflector work lamps, etc..., for lighitng. Swing arm desk lamps, mounted to a clamp of some kind, make easliy adjustable arms for flash units.

Also, yardsales, thrift shops, church bazaars, etc..., are good places to spend a few minutes once in a while.

i got 5 backgrounds here... we use this in our digital studio... im a professional photographer... its up to you how you will use them,,you can change their colors in adobe photoshop... hope you will like them! cheers! =)
http://i188.photobucket.com/albums/z118/...
http://i188.photobucket.com/albums/z118/...
http://i188.photobucket.com/albums/z118/...
http://i188.photobucket.com/albums/z118/...
http://i188.photobucket.com/albums/z118/...

I just used PCP pipe from the local hardware store and then bought the cheapest fabric I could find from Walmart in the colors I wanted. I just used shower curtain rings to hang it up... it's working well for me. Also, there are really cheap backdrops on ebay if that interests you.

You can get a floor to ceiling light colored tarp at Home Depot for $20 and a work light for less than that.
Start shooting.

#1) a frosted shower curtain with a gel covered light coming through the back
#2) Rice paper window shade from Pier One
#3) King sized Velux blanket (or fleece)...especially good in black because no reflection
#4) Create a wooden frame about 5 x 6 feet and stack soda cans with the shinny, concave end out for a very modern look.
#5) Wrinkled foil

edited to add - paneling from hardware store - wood and stone like
builders glass blocks
room dividers