As any weaving fan out there knows, looms these days are rater pricey- even for a basic model! There's also the fact that they're rather hard to find in stores and also take up quite a bit of room once they're home. Fear not though, my dear weavers, for I present to you the answer to all our prayers! :D
Cardboard. You can find it just about anywhere. I recommend using something about the size of an egg box. The bigger your loom the more possibilities but the harder it is to carry it around with you.
I recommend that you DO NOT use corrugated cardboard for this project, sorry. :(
Use a ruler to mark every 8th of an inch across the top and bottom of your cardboard piece.
DO NOT ROTATE YOUR RULER WHEN YOU GO TO MARK THE OPPOSITE END. Your markings MUST match up exactly or your weft (what you weave your fabric through) will be skewed!
Cut your slits!
Try to keep them all relatively the same length (about half and inch). The more uniform they are the more even the top/bottom of your weaving will be when you push all your yarn up. :)
Wrap your weft through the slits and wrap your board.
Your weft can be anything from yarn to simple string but be aware that unless you comb your weaving nice and tight that you WILL be able to see your weft thread in your weaving when you're done.
Make sure you keep the weft thread as tight as possible without bending your board.
Connect the two ends at the back of your loom and tie them off. You may need a friendly finger (lol) to help.
You can now start weaving! :D