Hi Julia and welcome to the forum.
Which boat to start with will depend a lot on what you want to do with it.
Do you just want to go out for a few hours and sail around, develop your sail handling skill? Then a small boat like a Sunfish or a Hobie Cat
would be a great, low cost option.
Do you want to do the same but take a friend or two with you, maybe carry a cooler and stop at a beach to have lunch then sail home? Something a little bigger would be better.
Do you want something that would be like a small cruiser that you could actually spend a night or weekend with a bunk and room for a head
or portapotty, small galley
? Now you need something even bigger. For this the Compac would work. Also West Wight Potters are very popular small cruisers.
Cost? Do you have a car or truck that can pull a trailer? I not, you will have to pay some kind of storage
or find a friend to tow for you. If the boat is in reasonable condition then the costs will be minimal until it's time for a repair or replacement. Sails
will last for years but you could spend a few hundred even for used replacements
? Outboards are usually reliable and have minimal maintenance
costs but ethanol gas can play havoc with the carbs and that could cost a hundred or two.
If the rigging
needs replacing that could be a few hundred or more, depending on the boat.
One way to minimize all this is to check out all the expensive bits on the boat before you buy. If you don't feel you have the expertise there are plenty of boaters in south FL that could help out.