Where do you get your Continue Professional Education (CPE) credits?

I looked through the stacks but couldn't find a definitive post on great places to earn FREE CPE/CEUs. I have several certifications that will be coming up for renewal, and I'm trying to be selective about what I am going to renew (cost is a factor). Does anyone have CPE suggestions? Free is always lovely, but I am not opposed to paid either.

Also, I am currently self-employed so no employer to help pay or reduce the cost.

cpe cybersecurity education