As far as how much they get paid, it really is dependant upon the dog walker and the owner. Usually, they get paid by the length of the walk, and the size/handability of the dog. Small, easy dogs are not going to be as difficult to walk as larger dogs, so they generally charge less. Usually, for more than one dog, there would be a discount for the second dog (even if walked seperately).
Now, as far as training on walk, usually the walker will work on LLW, but other than that, it depends on the walker and what the owner wants.
2 1/2 year old female ferret
~7 year old male ferret
Goodbye, Rosey. You were the best girl I could have asked for. 10/15/96-03/08/13