Today's Musicians Friend stupid deal of the day is a ProCo stageMaster 24x4 100ft snake for $299. Good deal?
It's not a bad deal, but I think that one should buy as long of a snake as is reasonable for the events that they do. If you mix side-of-stage normally (doable, but certainly not ideal) and don't ever plan on being out in the audience area, a 100' snake should work fine.
I prefer at LEAST 150', but 200' is better - I like to have some slack in my cable, if you know what I mean. When you're running the snake cable over doorways and get forced to move FOH to the back corner because the event planner doesn't like all that equipment blocking their guests' sight lines, you'll be thankful for that extra length.