Should I buy a phone online from Amazon, Ebay or Aliexpress ?

Hi, is it good idea to buy a smartphone online from Amazon, Ebay or Aliexpress ? Some phones are cheaper there in comparison to standard stores.

Online marketplaces like Amazon, eBay or AliExpress have their advantages, but they also may have some disadvantages. The advantage is you can usually purchase some products for better price. The disadvantage is that product can not always match your expectations. To minimise this, there are feedback based seller profiles, so you can check the sellers' feedbacks and ratings to evaluate their trustworthy.

For example some sellers on eBay are marked as "Top Rated Seller". The ratings are assigned according to seller's previous activity, so there are more reputable sellers and less reputable sellers. But you can find not only small sellers on these marketplaces. Also some popular retail stores are selling products there.