In many parts of the world, a service dog is considered a valuable caregiver and are actually paid. The fee covered food and toys for the dog and saves the health system up to 29,000 pounds a year for a human caregiver.

And costs incurred may also be a deduction for income tax purposes for the handler in some countries. Check into it in your country.

In Canada, typically it is only the costs to maintain service dogs provided by non-profit societies that can be deducted, but save your receipts and ask your tax man in case the laws have changed in the last year. 
In the US, you can deduct the costs for an owner-trained service or assistance dog (but not an emotional support dog or therapy dog).