I can't give any specifics in regards to a sports residency, but I am currently enrolled in an orthopedic residency. In general, your salary will depend on the amount of patient care you give. In my current residency I receive a full salary but I still have 40 hours of patient care on top of mentorship and additional course work. The program is 2 years and there is a approximately $6,000 fee. They pay for the OCS examination if I choose to take it upon completion. Also, I have an actual position with the company and if I stay following completion of the residency, they will pay me back the $6,000 over a two year period as long as I stay.
Other residencies I considered were only 1 year in length with 30 hours of patient care and 3/4 salary with a similar fee. None of these guaranteed any sort of employment following completion. I also saw some residencies that paid more in the range of 50% of a normal salary with a fee and no guaranteed employment, stay very far away from these options.