Need a form for sponsorship -- not sure if Gravity Forms will work

I need to create a form that would allow one to sponsor a runner in a marathon. What we want to do is have each of the 26 miles available to be sponsored. Each mile would be available for an increment of 100 dollars. So mile 1 is $100 and mile 10 is $1000. I'd like to show each mile and whether it is available for sponsorship and how much the sponsorship will cost. If it is available, then I will need to have the sponsor fill in a form, pay for their sponsorship at paypal and then have the list of available miles updated automatically. Is this possible with gravity forms? I guess the recently sponsored mile would have to be dynamically updated? We are not yet sure whether we want to show the person's name who sponsored or just mark the mile as sponsored. Can you help me out 1) by letting me know whether this is possible with Gravity Forms and 2) point me in the right direction to get me started.
Thanks so much!!