Most of these kids, especially at G5 schools, aren't worth much coming out of high school. So an incentive-laden contract would look something like this:
1-Show up on campus = $5k (essentially a signing bonus)
2-Crack the 2-Deep = $5k
3-Named a starter = $10k
4-All conference = $20k
5-All American = $50k
*Buyout. In the event of a transfer, all money paid to the athlete must be paid back to the collective.
For QBs the scale is probably different simply due to the importance of the position.