$2,000 seems like a lot of money for banner tow training. Towing banners does not require a specific endorsement and the training shouldn't take a lot of flight time. Mine consisted of a couple of hours of ground school followed by 3-4 flights lasting around 30 minutes each.
If it includes the tailwheel endorsement, then it's not so bad. I used to teach tailwheel and it takes people 5-10 hours to be proficient enough for a sign off.
I think banner towing is some of the most challenging and rewarding flying you can do, so if you have the opportunity to do it I would jump on it.