I suppose this would depend on what skills one has, but here are a few jobs that one can do without a ton of training or up front costs.....
1) Gutter cleaning...(requires ladders, not too tall in Florida)
2) Window cleaning.
3) house cleaning
4) Lawn mowing and trimming
5) Power washing houses. (requires a pressure washer, etc)
6) interior painting (requires some skill and technique)
7) Carpet cleaning
8) Child care (BIG responsibility)
9) Shopping for people
10) Dog walking
11) Car waxing/detailing
12) Errand running
13) Snow shoveling....oops, that is just up here
Also, sometimes one can use some of their life skills to earn extra money...like if you were a teacher, you could tutor. If you were in the trades, you can work at a big box Home Depot type store or home center.
If you know how to type, you can prepare resumes, term papers, etc.
I know there may be some snags with some of these, and I have no disrespect to those who do some of the above professionally.....these were just a few things that popped into my head in response to the question.
Frank D.