I use washable pee pads for Joey, and they also are great for cleaning up accidents. You can use an old towel, but don't wash it with things that you don't want to spread the scent to. They also sell super absorbent clothes. Just spay the area place the towel on it, and step on the towel and most of urine comes up. Spray again, this time leaving the spot to dry naturally. It takes time for the enzymes to work.
Here's a link with low cost clinics in California.
Low Cost Spay/Neuter Resources for California