Cheap prices might mean bad quality stickers, dont buy a batch too big to begin with! Also if you do go online be ready to get a lot of orders. You also need to be ready to comply. And one very important thing is to have perfect stencils. I have Izos Zhanchi fitted stickers and ALL of them have one bad corner sticker. That sticker is always the first to chip, and once it does, it is basically ruined. If your stickers are imperfect and dont fit the puzzle, they will chip very fast even if you have high price quality vinyl.
As for colours, I'd go with half bright set for starters (regular red and blue) and maybe a full bright with fluorescent red + a lighter blue. You might also want 1-3 choices of yellow, blue and green because those are the colours that differentiate cubers afaik. Most just prefer fluro orange and fluro/regular red, so a variety of those colours wont be necessary to begin with. Also make sure your stickers are big enough so that they cover enough (But not too much!) of the piece. Too little and you will look like a cheapskate + it will hurt lookahead and too much and they will chip fast = same result.
I'm willing to test them out too

Good luck with it; you can be succesfull if you can match IZO's prices with even decent customer service. IZO's flaw is that customer service is absolute s**t. thecubicle stickers are awesome but a bit on the pricy price for international customers as you have to buy for 15 dollars worth to get free shipping.