Are you looking for answers to your questions or just for more questions?
If more questions...
6) Where is it safe to fly?
If answers...
1) Figure about $300 all told. That should get you a transmitter, all the gear for the plane, the FB kit or sheets of foam, a battery and a battery charger. MOST of that can be re-used on future planes though. Outside the cost of the bare kit, I spend about $50 on the electronics for a new plane assuming I'm just binding to the same transmitter and using the batteries I already bought.
2) Do some research, but even that can lead you astray. I own a Frsky Taranis X9 Light transmitter which I almost NEVER use, and is bound to like 2 planes right now. I also own a budget Flysky FS-I6x, which is a cheap transmitter that does EVERYTHING I need and has 18 planes bound to it. I know if I ever do anything really complicated I'll probably have to learn to use the Taranis. But right now the Flysky does the trick, even when doing Elevon mixes.
3) Any broad high wing plane should do well to start. The FT Explorer is a great example, but my son learned on the Bushwacker. Your second plane should be the scout. You'll never stop loving the scout.
4) Roughly the first number is the size of the stator, though some manufacturers use the can size. Basically it's how big the motor is. Bigger motors have more torque. The "KV" number is how many times it will spin per battery cell at full speed...roughly. Higher numbers spin faster, and generally require smaller props. This is really a more complex topic than can be covered quickly.
5) Check your CRAP:
C = Control Surfaces. Everything moves freely and the correct way when you move the transmitter controls
R = Rips and tears. Look the plane over and make sure nothing is broken that will affect flying. Nothing worse than thinking "this plane is flying funny" then watching the rudder fall off.
A = Angles. The rudder should be perpendicular to the tail surface. The tail surface should be parallel with the average plane of the wings both from the side and from the front. If something is aligned wonky, the plane will fly wonky (or not at all)
P = Power. You did hook up the battery, right? Are you using a throttle lock switch? Did you turn that off?
Those things are in addition to the CG check, which is, of course, also very important.
6) Open field with good lines of sight where you have permission to fly. I think public parks are generally ok, but make sure you're not flying over people (or pets) or in any way where you may irritate someone. When you fly, you represent not only yourself but our sport in general.
