I built this loom this week out of scrap lumber I got at the Habitat for Humanity ReStore (I think the 2×2 and the two 1×4 pieces cost me $2 or less), 4 carriage bolts, 2 long square dowels & a lot of popsicle/craft sticks & hot glue (for the rigid heddle reed), Peaches & Creme cotton yarn. I used half-filled water bottles tied in little fabric bags for the weights. The shed stick is another piece of scrap wood (I think it is a piece of clapboard, I got it for a quarter) that I sanded a bit and wrapped with blue duct tape.
The “reed” or the “rigid heddle” is an eye & slot heddle made from craft/popsicle sticks. It has 48 sticks across, each with a hole drilled in the center. Half of the strings for the warp go through those holes. The other half of the strings go through the slots in between the sticks. I used two long flat dowels to glue the sticks onto so the thing would be wide enough. And then glued more craft sticks on the top and bottom ends to help keep them on there (FYI, I was going to put another set of square dowels on top and bottom, but the hot glue dries on one end before I could get it to the other end!).
I wrote up a bunch of notes to share with you about how I constructed the thing, in case you want to make one and need help that you cannot find elsewhere, but I will have to type those up another day!