There are many players buying SWTOR Credits online these days, and this method is relatively simple and easy. However, with the popularity of Star Wars The Old Republic, a group of unscrupulous merchants began to illegally sell SWTOR Credits on the Internet. So you still have to choose carefully when buying SWTOR Credits, so as not to be deceived.
In fact, there are many ways to earn SWTOR Credits in the game, including: trading, collecting, crafting, looting, etc. As long as you're patient enough, you'll get plenty of SWTOR Credits in return.
Of course, if you insist on buying SWTOR Credits online, then I can give you a recommendation. IGGM is a safe and legal site that often issues coupons.