Hi XXXXXXX~
Costs for something like this can vary from city to city and from vet clinic to vet clinic. The best I can do is tell you that it woudln't be out of the ordinary to have this kind of procedure cost upwards of several hundred dollars.
The best way to get an idea of what it will cost in your area is to call around to local vet clinics and ask for an estimate for this type of tumor removal. Trust me, clinics get these types of calls all the time and will have no problem giving you a ballpark estimate of what it will run you to have it removed.
You can also ask your regular vet about their cost and then tell them what the competing prices are...often your own vet will match a cheaper cost, rather than risk losing you as a client and your dog as their patient.
I hope this helps.
Certified Veterinary Technician
Associates Degree in Veterinary Technology. State and Nationally certified.