Do you pay them just for that hour, or more to make it worth their time?

We have a funeral visitation to go to on Thursday, and obviously aren't bringing the girls. My mom babysits 90% of the time, but the visitation is 3 blocks from us and my mom lives 8 miles away, so packing the girls up in the snow to go there for an hour isn't worth it. We asked our occasional sitter if she's available and she is. She's 15 so we pick her up and she's not too much per hour, but I'm wondering if we double it? More? Not sure how to handle it since it's only an hour, and I would feel bad just giving her that amount.