Our PetsMart has an arrangement with two different SPCA's. They alternate months. The money charged all goes to the SPCA. In addition, PetsMart makes a donation over and above that fee for every cat that is adopted from there. One SPCA charges $129.00, one charges $169.00. (That's Canadian money). They are all spayed or neutered, and have their shots. Kittens are about $20 more, they seldom have kittens.
I used to go and cry, until I adopted a second cat. Then I knew I was doing all I could, because two is my limit, both in time, and in potential vet bills.
Our local PetValu store (a very nice discount pet food place) has just started bringing in cats from the local rescue society. These are mostly ferals, and they are fostered but a network of local people.
I went today, and found that Francis has found a home. He is a lovely black cat, with a white bib, and is a friendly even tempered baby. If you pick him up, he just goes limp in your arms. He was adopted out on July 1. Then he came back, apparently the new family said that he bit them. I was really upset. He "bit" me too. He put his mouth on my hand when I moved unexpectedly. That was not biting. If the family didn't like that behaviour, I am glad they brought him back. He's really happy with his new family now.
Instead of small crates, they keep their cats in huge cages, with shelves on the sides, and tons of toys and blankets. And starting with Francis, they just leave the cate doors open, so the cats have the run of the store. (They only have two at at time). Its like cat heaven, they can try out all of the cat trees, open bags of kibble, run and hide, and they have all of the customers play with them. I think since March, when they first started bringing in cats for adoption, they have placed about 25 cats. Even the grumpy older cats who don't like anybody. Its not a huge program, but it does make a difference in the lives ot the cats that go through there.