Swapping out a axel boot is usually a pretty painless process, Provided you have the tools for the job. Replacement boots can be had as cheap as $20-$30 and assuming your only doing the one its a 3-4 hour job. If its a fresh tear you can drive on it a bit without too much worry but if dirt gets in the CV joint it will cause irreversible damage very fast. If all the grease has been ejected from the torn boot or you can feel grit in the boot then its time to replace the whole Joint or in most cases just swap the axel.
If it turns out to be an axel swap it can cost you a bit more than a hundred dollars. you can get new axels online for about $125 shipped, the install process is easier than replacing the boots by themselves and doesn't require those damn C-clips.
TLDR - If the damage is fresh and the CV joint is still clean you should be OK to drive until payday, if you have time and $20 before then you can swap out a boot in an afternoon.
13 WRX Hatch - Cobb OTS Stage 1