Do any of the local schools give adult education classes in the evenings? I had a CPR course as part of a program in high school and I know the teachers then would run the same class in the evenings as part of the adult program. You might have to take the whole auto shop course or something else to get the safety portion in the beginning, but that might be somehting to do during retirement. Since they were put on by the public school system they are free.
Now that I'm thinking of it we didn't have the CPR instruction in any of the auto shop or electronics classes, we all went down to the nursing/health care room and were taught there. So see if the local schools teach nursing or health care assitant classes in the evenings, you will probably get a lot more than just CPR.