+1

$100 is worth it for FO, if you have the time to fly the extra segments. As someone earlier said, only you can value your time, but I certainly appreciated my time as an FO and it was far better than just holding an Amex.

BumpMeVoucherMeATL's plan of LAX-SFO runs will work, but requires spending more money and adding in a completely unplanned trip to the west coast just to fly around. The other plan for PM/DM requires you spending $900 in CC fees, $800+ for MRs, and $60k in real or manufactured spending to hit the mileage boosts. While all I know so far is you're a student in the midwest seeking FO for $100 more on already-planned-trips, those factors alone don't strike me as belonging to someone who's trying to dump even more money out there to push for PM/DM.

The only other thing I would suggest, and only if you want to and can afford it, is to plan an actual vacation. Perhaps you can find a good MR/SR deal out of one of your cities that is a 2-stop in either direction, and then spend a weekend or a few days exploring somewhere new. You'll get the segments on a cheap fare, and also minimize any possible IRROPS during your actual planned trips. And since you're getting the segments actually on your way to/from somewhere, it'll be less boring than bouncing back and forth between airports on a segment run.