How much is it appropriate to charge someone to advertise their
business on the web site of a youth sports program?

How many people will be viewing their add and how many potential
customers would actually use there services? Size of avdertisment? How
much text will be included in the add?

Probably very little text - maybe not much more than a small icon and
10 - 15 words of text.

The site, according to a counter I use on aplus.net, gets about 7,000
hits a year.  About 5,000 of the hits are within one week (when there
is a big tournament).

My understanding is that the counter actually understates the true
number of web site accesses since visitors who have a static ip may be
counted as only one visit even though they may visit the site multiple
times.