Greetings,
I have been in the computer business for over 20 years. Much of what I do is service PC's for my clients. So, I guess I am in the PC Repair business also. I have only ever worked with local suppliers who build white boxes for resale. They have the resources to buy for Tech Data or the other distributors. If I were to buy from a distributor, I would have to pay freight and deal with RMA's and other crap like that. I buy from a company that does retail sales as well as selling to resellers and I also work with another company that sell to resellers and some corporate.
I buy from them at about 10% over their cost, but they have greater volume so they get discounts. If I ever have a problem with a part, I take it to them and they replace it on the spot. As an example, tomorrow I will take a floppy drive and a mouse back to them and they will replace it on the spot. Had a bought directly for a distributor, I would have to deal with the RMA issues myself. I may save a buck or two, but I lose it fast on returns.
Develop a relationship with the owner and the sales team. You need to have people who know you and will work with you. I have been buying from the same people for over 15 years. I have been through many sales reps, but the owners know me and know that I am consistantly buying from them.
Also, don't worry about price. You should be making your money on service. Sell service, not price. Under promise and over deliver. Anyone can fix computers, not everyone can solve peoples computer problems.
Let me know if you want to know more.
Marc