A typical P51D is not a beginner's airplane.

You should consider getting a trainer plane and finding an instructor. According to the AMA club locator:
http://www.ama-dist-8.org/Clubs/Locator.php
there are 3 RC clubs within 20 miles of winter haven. Most clubs provide free instruction to members.



At the top of the Beginner forum is a "sticky" posted by RCKen
http://www.rcuniverse.com/forum/m_4537845/tm.htm
It is a pretty broad listing of trainer airplanes that are available. All use glow fuel powered engines.

If you want electric power, there are several electric trainers available; these are the ones I've seen:
Hobbico has one called "ElectraStar" or something similar; and the Superstar EP.
SIG has an electric version of their "Kadet LT series trainer"
Hobby-Lobby has an electric Telemaster

As far as the $20 simulator: I'm guessing it's a $20 USB adapter to hook your transmitter to the computer and a copy of FMS software which is available as a free download. I've never used FMS but a lot of people do. It will not have the graphics or physics of a $200 package but it could help the learning curve.