First off, figure out exactly what you want and what route you want to go. All your questions can lead to a ton of different answers.
Don't deal with petco/petsmart for animals. They have ton of shows, especially in Florida where you can pick up a healthy animal for a lot cheaper. You've just got to decide what you want and where you want to go before you start buying all types of random species.
Also, avoid impulse buys please. Not saying you're the type but this is the reason a lot of animals end up on craigslist and what not.