I have decided to make a midp2 only game, but what your saying is that if the game is made with suns wtk then it will run on all phones supporting midp2? So the special developing kits for each phone is just if you want special features or a little bit extra performance?
Unless you're making a Hello World app, it probably won't. But using the proprietary SDKs doesn't mean it will work on the actual phones either. Unfortunately the only way to know for sure that it works on a phone is to test it on the device itself. The specialized SDKs are good when you want to use proprietary APIs, or check that the app looks good on the target phones, because they will have emulators with the right screen size, key configuration (apart from the ITU-9 keys, all other keycodes don't have standard values), supported media types, etc. If you are lucky you might get emulators that emulate the bugs and not-properly-defined-by-the-specs behaviour of the phones but you can't count on that.
I thought I had to use each vendors developer kit to compile the game for their phones even though they support midp2.. ? (because of small differences in the phones) But this is my first game so i dont know alot..thats why i was thinking about making it work in suns wtk first.
If you aren't using any proprietary APIs then it doesn't matter if you compile with the WTK or with the proprietary SDK. The bytecode generated is the same (or at least it should be).
j2mepolish looks great,except you have to buy a license to sell the games.. I dont even have a company im just a student starting out, I cant pay 300euro to sell a game.
AFAIK, you only need a license if you use Robert's classes, like the J2MEPolish GUI. If you just use it as a build environment you don't need to pay for a license.