I posted this last year, but to make it easier for me to find the post I'm creating it's own thread :-)
Need a hotspot on a budget? Check out http://freedompop.com
If they operate in your area it's certainly worth checking out...
They give you 500MB of data FREE each month. Based on what @chris has said, that's way more than you'd need. (It's reported that axtime uses about 20MB per event)
They have pre-owned 3G hotspots for $30 (you don't need 4G/LTE for axtime).
So for $30 ... you have a hotspot you should be able to use with no data fees and no contract. You'd just have to make sure nobody accidentally opens facbook or instagram on your timing network ;-)