Hello Nancy- This depends on many things, including how close you are to the shore and also to wetlands in general.
Many factors- but if you're looking for a ballpark-
Figure $10- 15K for the septic system- for a 3-4 bedroom
For the well- figure about $10K total. Assuming they don't have to dig down a tremendous amount. No way to tell really.
For wells, nobody will give you a guaranteed price, and they will not even guarantee that you will get adequate GPM, etc. Its all a crapshoot- but they can give you their professional advice.
You should contact the Town Offices and talk with the Board of Health. They will give you the regs and the setbacks for the town, etc.
Any other questions, please contact me if you'd like. Thanks and good luck,