Affiliate Marketing Secrets

HI all
Im looking to start my own ebay business but i dont want to start buying massive wholesale joblots of stuff to start with. Im looking to start of small and try to order maybe a few things of each different product just to see which one slls more and continue in that direction.
I have already found a niche that i want to be in, its kind of based on what my job is, I know people personally in this field and also have a bit off experience installing them , so i feel that i do know enough about the products and how they work to try and make this happen , it also gives me an added advantage as i can have two different selling fields.
Does anyone know some sites online where i can sign up and find prices. I can get trade prices from wholesalers in my local area , but i want to pay what they pay, not what thier mark up is.
My niche is electrical parts , components , cable , I can also sub contract the work with various people i know and supply the materials on a cost price basis , to maybe earn some money of the installation itself.
cheers