We used to do that when I was younger. I was just a lkid, so I have no idea about the affect on your budget.... but, I do know we did alot of sightseeing stuff, day trips... showing them around. They were here just a few weeks, so all we could really do was daytrips. Groceries went up, not only the fact that you are feeding one more...I think we cooked a little more.. so the kid could experience real like traditional american food. Plus there was the "extra" food we bought. We had one from SPain who came a more than once... when she was here, she LOVED peanut butter.... all of the PB (w/chocolate) things we have here are very different from what she was used to. Maybe this was my parents choice, but they bought and paid for lots of different food items for her to try etc..... I know they come with money, but I am not sure what they are supposed to use it on. For us, I know we paid for stuff for her, when we were out doing "family" things.... It was a great experience for our family! One of our students has been back on her own several time... and brought some family with her.... My parents have visited her is Spain 2 times, most recently.. last year when she got married!
Enjoy it and have a great time!