There is not a slot for bills. I usually fold up my bills and put them into the coin purse area.
The ludlow works out best for just "quick trips". I use with a small evening bag or a small day bag.
I have the Ludlow in Bronze Vernis and I love it! I don't put my bills in the coin slot, however. (Annoying to mix change and bills.) I use the one card pocket under the snap for folded bills. I can fit two cards in one of the other card slots and another card right behind those two. Hope this makes sense!