Instead of just finding something on the Internetand Liking it on Facebook, you may soon be able to outright buy it, using a new Facebook payments system.

According to AllThingsD, Facebook is testing a new payment tool “would allow online shoppers to make purchases on mobile apps using their Facebook login information, according to sources familiar with the company‚Äôs plans.”

If the testing is successful, a Facebook payment tool would be in direct competition with and be a potentially huge blow to services like PayPal. Since users could pay for online items using their existing Facebook credentials, it would streamline an online payment transaction even more.

This is likely what Facebook is counting on. But online payment is a tricky sector to work in, since it is replete with potential disasters that involve users’ money. Facebook could be in for a rude awakening when payment theory becomes payment practice.