1. Make sure you have a way to check the resistance on your atty before you fire it. This is especially important when you are going to use it on a mechanical mod. Do you have a regulated device or something that is VV/VW? They are a little safer when you first begin, plus many of them have an ohm reader built in.
2. DO NOT start out building super low resistant coils (sub ohm). If that is your ultimate goal, wait until you have a better handle on rebuilding.
3. There are a lot of options with wick material and styles of build. I recommend getting some plain old silica and 32 gauge Kanthal to begin with. Again, once you have some skill, then maybe venture into micro coil, SS mesh, etc...
As far as what RBA to choose, you really should start out with a dripper. The Igo-L or the Igo-W are very economical and have a lot of fans. I prefer RBAs that use a tank, but the ones that work well with silica are a bit out of your price range. You should look into the Fogger v2 or the Rocket Tank , if you are looking into tanks.
Genesis style atomizers are difficult for newbies. Even the RSST, which is touted as a beginner genesis, is still pretty tough to get working with SS mesh.