What are the costs to become a foster parent?

I'm not asking for a specific dollar amount, I'm asking what you have to pay for. My husband and I are just starting to look into becoming foster parents, but can't find a straight forward answer on what the different costs are.

We are in the US.

I also want to add, we would like to adopt through foster care when given the opportunity. What costs would we be looking at for that as well?