anyone using bluetooth obd2 scanner app?

I need an obd2 scan tool so in looking at my options it doesn't appear to be much more to get one that plugs into the obd2 port and bluetooth streams data to an app (i use an iphone) does anyone have a recomendation or first hand experience with one? I know there is a fairly decent option on amazon for $15 but looking up codes on a computer after the fact seems like a pain. I'd like to know on the spot what the code is and means.