Cat supplies for feral cats (Vancouver WA)

We are capturing 6 feral kittens/3 adults to spay/neuter and vaccinate. We are looking for FREE: cat tree or two, food, kitty litter, junk towels to keep them comfy while awaiting their appointments and recovering from surgery. It will likely take 3 months to get them all helped since everyone is very backed up. Thank you for helping if you can!