I use an equine dentist who does nothing but teeth. He usually charges me about $75.00 - $150.00 for work, depending on how much work the horse needs done. However prices can vary around the country.
This is just my opinion, but I personally can not make a decision based on what someone tells me over the phone. I would think the vet would need to see the horse, to decide if the tooth needs to be pulled or not.
I have had a rescue horse that needed caps ground off because they had not shed. (Caps are like baby teeth, they are supposed to fall out but sometimes don't.) This particular horse could not really close his mouth due to the caps. I've also had wolf teeth pulled. Sometimes they are growing wrong and interfere with the bit in the horse's mouth. However, I have never had a vet make a call that the tooth should be pulled from a phone call. AND, I have never had a vet make a call that a tooth DID NOT need to be pulled, based on a phone call! Unless these are magic vets, they would need to actually SEE the horse to know the real situation and decide if the tooth should be pulled or not.
Again, this is just my own opinion. I am inclined, myself, to talk to a vet that I trust. I think that's the best thing to do.