When you shop online pay attention on feedback. Whether it's a person or a shop seller can easily cheat on you with quality, sizes or not even send you your goods.
But when you see that a lot people have already bought many stuff there and they are satisfied with it - go for it.
I had an unpleasant situation one time when I wasn't careful and they simply deceived me. The price was low and I didn't lose much money but still it was pretty frustrating to be fooled.