$2750 for 121 northern red oak trees, 2 white oaks, and 4 black oaks definitely seems rather low -- I don't know the quality, so its impossible to be an armchair "computer" quarterback when assessing timber values. On the other hand of the spectrum, $75,000 for those trees is also EXTREMELY unreasonable -- way, way too high!
Some Simple Math:
$2750 for 129 trees comes out to $21.32/tree.
$2750 for 14,500 board feet comes out to $0.19/bf.
Granted, these seem like some pretty small trees: 13,660 bf for 121 northern red oaks comes out to an average of 113 bf/tree -- any particular reason why you're harvesting such small trees? Are they damaged? Are they dead? Are you clearing the land?
Too many unanswered questions and too many unknowns to provide you with adequate answers, which is exactly why all timber / log value assessments need to be conducted on-site by a trusted professional.
My advice: Contact a local professional consulting forester to provide you with on-site guidance and timber marketing advice!