I just picked up the car and the ABS had 5 fault codes for ABS pump failure and right front/right rear speed sensors. (no idea on the actual codes). So to confirm i could drive it around for a bit and see if i can get the codes and then come back but no reason they would lie about that - they've been good to work with thus far. In other words, in this case, simply replacing the sensors wouldn't keep the ABS from cycling and then going off.
Here is the breakdown on the estimate that i did get though. I assume all new parts here since it wasn't noted otherwise:
1. Replace ACDelco ABS Pump Assembly/Modulator(w/Traction Control): Part: $1,100, Labor: $270.40 = $1,370.40
2. Replace Right Rear Wheel Hub with ABS Sensor(sensor is bad but bearing is good): Part: $230.53, Labor: $157.50 = $388.03
3. Replace Right Front Wheel Hub with ABS Sensor(No Signal from sensor but bearing is good): Part: $215.46, Labor: $201.50 = $416.96
The part prices for the hubs are not that far off of your $150 mark since they are new ( i assume you were talking about used). Not sure what they charge per hour though.