Is there any difference when buying a cell phone from the official store or a franchi

i'm looking to switch providers. all the big providers (sprint, verizon, etc...) basically cost the same thing for the plan family plan i was looking at. and when i was looking online for a decent pda phone, i found the palm centro smartphone.

when i went to to look at the phone they want 50 bucks after the rebate. and the same thing with wants 100 dollars for it after the rebate. (those are the only 3 that have this phone)

NOW, i went to radio shack to look at the phones in person before i committed to it and they would give me the palm centro smartphone for free if i got a two year agreement (which i was) with att.

my question is, is it any different buying my phone from a place like radioshack/bestbuy/walmart, then buying it at the official att/sprint/verizon/alltell store? my uncle bought his phone at radioshack and when something went wrong with it, sprint said go to radioshack and radioshack said go to sprint and they sent him back and forth for a week before he got any answers. i want to avoid this kind of situation. and if all the plans cost basically the same thing and i can get a free phone, it seems like the smart way to go.
the arsonist had oddly shaped feet...
I have had numerous problems with the phone that I bought from one of verizon's "authorized retailers." They signed me up for the wrong plan and then when I needed service they sent me to the Verizon corporate store, where I was told to go back to the retailer. My advice is to stick with the corporate stores only.