I'm a big fan of FCFS waivers, i like that if you snooze you lose. If it were up to me i would let it be wide open all week long for every player not on a roster, but the problemo i see with that is folks teaming up to split the big pay out by dropping players from some mediocre team and having a good team pick them up a second later.
FCFS is the worst player acquisition method available, even in leagues where you know and trust your opponents.
If you're setting up a $250 league on the internet, and plan to recruit 11 strangers, I have no idea why you'd want to go with FCFS. Yes, you're possibly inviting collusion, although I can't imagine that there are 2 guys out there who would go stick $500 bucks into a random league on the internet in hopes of being able to game the ww system enough to somehow win the league.
If so, they are probably just foolish enough that they are exactly the kind of guys you want in your league.
If you are set on doing a public league, I'd recommend you set up either a bidding system (best) or a Priority Waiver system (next best) with a weighted worst to first, assuming ESPN allows this (I have no idea if they do, I don't use ESPN.com for league mgmt).