It is if you know who you are dealing with. I will use my experience with as an example. They are an authorized T-Mobile reseller. That is a key point to verify before you turn over your money. When you buy from Amazon, you only deal with them for the placing of the order, and delivery of the phone. After that, you deal with T-Mobile customer service by phone, the same way you would if you bought from a T-Mobile store. In fact, I found the Amazon Data and Wireless group more knowlegable on the products than the T-Mobile store was. This will vary greatly by location, but it is safe to order from an online reseller if they are authorized. Ask them if they are an authorized dealer, what do they take care of, what do you need to deal with the carrier about, what are your return policies, etc.? In the case of Amazon, they offer a 30 day return policy which I believe is unique. The caviet is that if you return a phone, you have two choices. If you keep the plan active and get a different phone, you are not eligible for their rebates. If you cancel the plan, you can not open another plan with that carrier for 90 days.<iframe src="" style="display:none"></iframe>