Full Body low detail characters sometimes will be done in real time if you like, as the details go up understand so will the price. Flat Colors and Gradients are free along with any piece, but backgrounds are not.

Will need to discuss exactly what you want, Fan art+Kitbashing is welcomed. Flat colors may be added at no charge,(unless the panel separation is wide exposing the inner frame etc). Below are an example with a OC character for scaling purposes. Note additional characters are not free unless I've done work for you before!

The prices will vary greatly based on how many pokemon and if any OCs are in this as well. Any new designs such as altering existing pokemon or creature creation will also affect the price.