Sure. Where do you want to do it? How can you ensure credibility and spare part availability? I suggest that you have a few cheap smart phones which you can give as a backup for the customers to use while their phone is being repaired. Transfer the contacts and the sim into that backup phone. Then you have met their immediate need. Next , plug into the supply chain where you can call your spare parts dealer who will send them through your local bus driver or someone who travels everyday. Pay them some thing. Never ask for free help. Have a few basic spares like batteries etc. But who will repair them? If you can, good. But if you cant, then learn. You cant afford to depend on another mechanic who thinks that you are dependent on him. He should feel that you are providing him the job , though you can do it yourself.

You have to be in the market, facing customers and collecting repair jobs. That is the toughest and driven by credibility and face value. Of you can get some exclusive service center type contracts, it would be good branding.