You don't actually need a loom. They make it easier to transport your piece, but they tend to be an expensive item if you wind up not enjoying it. You can tie it to your belt at one end and a table leg at the other end, but this can be a hassle, if you need to get up. In my class, I use 3" C-clamps, which work well on most tables, and if no table is available you can clamp two onto a board. The string is tied to the screw part, so the cards are suspended between two points (basically a really tiny Oseberg loom). The same thing can be done using pillars, a chair, cardboard box, etc...
Wrap your weft string around a piece of cardboard or an empty toilet paper tube, and use a ruler as a beater. I prefer the wooden ones with a bevel, or a metal edge. The cardboard or TP tube can be used as a beater, but it doesn't last as long.
Probably the easiest way to make cards is to use a deck of playing cards. Use a sideways card to mark a square. Cut off the excess. Once I have a square card, I use it to mark the rest of the deck.
Use the x as your marker to punch a hole with a hole punch in each corner. Once you have one with four holes punched, I use it as a master to punch other cards. You can use the hole punch through the holes, or trace the holes onto the unpunched cards.
My apprentice Will discovered a faster way of punching the cards, using a two hole punch on the opposing edges of the card. You can punch more cards at a time, and consistent holes require less effort.
I recommend starting with cotton crotchet thread because it is not at all sticky. Try to avoid the one with the metallic wrap as this will probably get mangled as it passes through the cards. Sometimes thrift stores have bags with yarn, etc... Otherwise you can usually find these pretty cheap. You need two balls each of two colors in order to speed warp. If you want to only buy one ball, wrap about half of it onto an empty toilet paper tube, so you have two spools. Obviously, I recommend doing this before class starts. :)