Where can I sell an older model vending machine?

You should try selling it on E-bay that's probably the best option. However, other things you might want to try would be to contact local organizations that have people around alot such as churches. Many of these groups might be hesitant to buy the vending machine, but if they are a 501(c)(3) organization, they can give you a charitable gift receipt for your donation, which you could then use as a tax write off at the end of the year.

perhaps a mom and pop store that is locally owned and operated on a low budget. i know there are lots of such places in indy and surrounding areas. ebay would be pricy. If it is very old, try an antique shop.