How much would one expect to pay for a dog walking service?
This answer depends on how credible their dog walking service is. If it a fledgling company, then give them a decent amount around $5 to $10. If it a regular dog walker, then spend $10 to $20. This will show not only your appreciation on the job well done, but also add a minute amount of credibility to strengthen their company for the future.
If you mean a silver eagle (made from the 1980s to present) you can expect to pay $1-3 above silver spot for them. At the time of writing, you can expect to pay around $31-34 or so for one. Expect to pay about double that for a proof. Keep in mind that changes in silver prices will change the price of the coin.
How much can I expect to pay for limo service from downtown Indianapolis to the Indianapolis International airport?
You need to know what you expect from a fax service - for instance, how much you want to pay, whether online faxing is provided, the security of the service, the amount of customer service provided, whether you want to sign a contract and so on. Then you can find a fax service that supplies what you want.