Most of the tools you need are standard mechanics tools. Small 1/4 drive socket set (I also like nut drivers as they are more convenient sometimes), some small screw drives (standard & metric), hex drives (you will have to get specialty tools to find hex drivers small enough, or just use the normal L shaped sets, they work but are not as convenient). Several hobby companies make hex driver and screw driver sets for RC. Wiha tools also makes small hex drivers and I know their stuff is really good quality steel. Not trying to sell their goods, just relaying my opinion as I own several of their driver sets.

I would just buy what you can afford. Get the basics to get started, then upgrade as you can afford to do so. As long as you buy good stuff and stay away from the cheap import stuff as already stated, they will last forever.

Edit - Wanted to add: Craftsman makes a set of micro pliers that I use a lot for my RC stuff. Other people also make similar stuff.