Cheapest upgrade path to Pro Tools M Powered?

[doc.beats]

I apologize if this has been answered in the past, I searched and didn't find exactly what I was looking for.

Right now I've got an Audigy2 ZS with the front drive bay - this works well enough for my basic needs (I don't record much at home, I've got a mic + cheap behringer mixer that i'll use for occasional vocal percussion, mixtape drops, etc) but I'm increasingly being asked to submit beats in pro tools file format or to do work on a pro tools session file. Given that my monitors can accept digital out, and that I wouldn't be requiring the analog audio ins to do anything significant, is the Audiophile 2496 my best bet? You can easily find that for $100 or less and I haven't seen anything else that can compare. I don't need Mic Pre's or multiple audio-ins or anything else - essentially just the cheapest way to let a producer get access to Pro Tools.