$15 for a sketch of a character and background if desired. This could include an extra line pass if it's too shoddy.

$40+ for an indeterminate number of refinement passes on a colored sketch (Subject to discounts, should the commission not be as complex.) Also includes a simple background, if the focus is on the character rather than an object or whatever the character is wearing.

$60+ for concepts that do not have prepared references, wherein I have to personally source more than one image based on your descriptions. These receive extra attention and more check-ins during the work.

For 3D art, https://www.furaffinity.net/view/47932163/