Here are a few suggestions - savings vary depending on exactly where you are headed and whether you will be renting a car.

1) SEA/OAK and SEA/SJC are about $40 less than SEA/SFO
2) SFO/ABQ is about $40 less than SFO/SAF and departing out of OAK or SJC to either one is less than from SFO
3) ABQ/DEN is less than SAF/DEN
(If you a renting a car in New Mexico anyway, ABQ is only a hour from SAF.)
4) For DEN/STL purchase connecting flights thru MCI - DEN/STL 1 way is more than $600 on nonstops but connecting flights thru MCI are as low as $139.
5) STL/TPA is about $140 on Southwest, much less than STL/RSW
6) TPA/TLH is significantly less than RSW/TLH.
Rent a car in TPA and drive to RSW.
7) RDU/DCA - try RDU/IAD or RDU/BWI as alternatives.
8) DCA/EWR - try Amtrak - less money and more convenient.