First of all the freebie that you can add to your compost..I see you live in Florida so you should have access to seaweed. It will really spike your compost with added minerals..Also, not free but it can certainly be alot cheaper than buying fertilizer productsl:

Organic fertilizer-

4 parts seed meal
1/2 part agricultural lime
1/2 part dolomite lime

and for the best results add-
1 part bone meal
1/2-1 part kelp meal

you can buy this stuff in large sacks at grain and feed stores for much cheaper than a gardening store. You can mix your own in a garbage type container. It is so much cheaper to do it this way and it is really a complete way to maintain your precious soil...you might also check out prices on the internet...hoping you have the best garden ever..there really is nothing like growing your own food -going from being a kind of victim to what food is out there to taking charge of your destiny.
Cheers to magnificent healthy soil....pammy