Cannondale superx

I’ve been looking to get into gravel for awhile now and have been given the opportunity to purchase this bike.
What’s a reasonable price?

I know very little about these bikes.
Looks to be in very good shape,carbon wheel set,electric shift not sure what else.
Took it for a ride,seems fast,light and easy to toss around. Looking forward to any feedback good or bad.
TIA