Uhhh. Hoooooooooow??

No, seriously.

How.

This is not a comic descriptive situation I'd thought we were in. Like the bit where Pete was working through the court system to own the dreadnought the party crashed in Episode III. It never showed up again in the movies, ever. Yet in the comic, it did get salvaged with the new owner being chased by lawsuits, and then later turned into Mos Eisley spaceport. There's no way the guards could have all been gotten by just BB-8. Heck, even Finn and Rose would have needed to get the jump on the group to immediately take out one of the guards in order to have it be an even fight and keep one from running off!

At least we get to have the coin gun appearance! It's like super improbable aiming skills, except BB-8 the droid is more like BB-8 the frisbee machine. On the video game side, money-powered equipment tends to be some of the stronger end-game kind as well if it's not literally shooting money. These look like pretty big coins, so even only 8 will probably be enough to take the guard out. At the same time, fighting using money is expensive, so it's best to have a way to make more money if not starting with a large amount. I wonder now if this was all the little alien stuck inside BB, or if there's still more to be had for future guards.