I know this is not what you want to hear but you have to buy a good set of tools. I started out with the basic tool klit from EXI and shortly after I had to replace my 1.5 mm hex keys (after the first build). I ended up with the turnigy 1.5 mm hex keys and they served me well while I had them. Lasted way longer than the EXI brand. Now I have the Scorpoin 1.5 and 2.0 mm hex drivers and those are my go to hex keys. I need to invest in another 2.0mm and a 2.5, maybe a 3.0mm. I could get the cross tips and nut drivers but for now what I have works. Personally I would get the Scorpions, they are durable and long enough for any situation.
one more thing
They actually lock into position (Scorpion). Once you insert it, its a bit harder to get out. Amazing to have a tool hold in place.