CARDS
I like my bone set, but the shed is a little small for wool, while my wooden cards are too thick for the bands I tend to weave. Most of my cards are made of arborite. It's cheap, strong, and is often a wood grain design.
Looms are necessary if you want to be able to walk away from your work, but they do not have to be complicated nor expensive.
For my classes, I use two C-clamps on table tops and stretch the warp between the upright threads.
At home, I have 3 different loom designs.
The Osberg Loom - a simple design found still strung up in a Norse grave. This design needs a stool or bench, but has the benefit of collapsing into a handful of easily transported pieces of wood. A loop of thread or belt wrapped around the band down to my foot allows me to change the tension as needed. A later improvement was to create a string heddle from more dowelling as part of that tensioning device.
My first loom was based on a design from Collingwood's book. It has a friction clamp at one end, and a slot in the end where I use a pair of dowels and a hitch knot to secure the warp to the desired length. I have a wooden comb that can be secured with a bungee cord to serve as a warp seperator and tensioning device if I feel it is needed. If you use this style of loom, the friction clamp should be constructed from hardwood. (over the years, my pine slats have warped and now require the use of a C-clamp to hold the weaving in place)
For the Ethiopian curtain, I had to build a loom that would be wide enough to handle all of the cards, so I effectively built a multiple version of my Collingwood loom. I deeply regret not using hardwood, as the tension of the threads causes the loom itself to bend, requiring sections of the warp to be re-tensioned several times before weaving can begin.