Hey,
I can definitly help you out, i just had a german exchange student stay with me for the past year.
First off, we used YFU(youth for understanding). You can chose your student, they will send you a few different profiles and you choose who you want. Some students wish to stay for 2 semesters, other kids only want to stay for 1. As for financial aid with food, no. It is your responsibility. You are going to be volunteering to take in a student, so you shouldnt take on something you cant handle. Here are some tips if you do have the student come:
First off, when they arrive, maybe have some pictures of your community on the walls in their room. Have a map of the united states and make an "X" wherever your town is. Have a bowl of interesting candy on their desk as well, try to look for exotic/plain out weird candy, that way the exchange student gets a taste of the different candies in the US. Our exchange student loved it, he had never seen a few of the things we had.
Next, make sure to treat them as family all the time. If you give chores to your other children or would give chores to children if you had some, give the exchange student chores. They want to feel at home and if you give special treatment they will enjoy it yes, but they will begin to get antsy in their free time as did our student. If you would ground one of your kids for one reason, ground the exchange student for that reason if they do something wrong, dont feel bad because they arent really your kid, they are living with you for a year, so they are for the time.
Next make sure to get them involved with school. Work it out so you know what sports/clubs your student participates in at home, so that when they arrive you can take them to school and sign them up for those same activities and maybe some others that sound interesting.
Take your student to large cities in the US. If you can, go to New York, Philadelphia, Washington DC, and places like that. Take them to the tourist spots, show the white house and stuff...taht stuff seems boring to us, but it is incredibly amazing to them.
email me if you have more questions