The $500 sounds high to me too, but having to bring another person to assist may be part of it. Factor in tho, how much you would have lost had calf and momma both died. More than $500. There's 'cost' and then there is 'value'.
$45 just for the 'house call' itself here, if mine comes out the 25 miles one way... more if it's an emergency where she has to drop what else she's doing and get on the road. Whatever she actually does on the call is extra of course. That $45 is just the travel, and if it's on her scheduled day of farm calls (all 3 vets here schedule farm calls on Wed).
I took one in last year on an hour's notice to the vet that didn't clean out and was beginning to show signs of infection. Clean out, checked her reproduction tract, a couple of shots, 2 boluses and it was less than $200--a bargain imo, tho I 'should' have been able to do it all myself.
You'll need to establish that Client/vet relationship anyway if you are going to need any prescriptions due to the new regs.