$16 bucks sounds like a fair price, if it works with your database. FMGo does not support plugins and FM also does not have any functions to read the data from any ports. If it works with FMGo then that's the route I would take.
There's a solution when using a swipe reader with integrated keyboard driver.
MagTek is among my recommendations:
• iDynamo with Lightning plug
• BulleT with Bluetooth connection
I have no experiences with those since I've built up the interface $20.- iApp which serves a a middleware to FMGo.
Any feedback appreciated. 'specially on the BulleT and iDynamo products.