flea markets, farmer's markets, parades, local craft stores might even buy your hoops to resell
you could even go to the park where children will be playing and set up a little space with your hoops.
Try local events that your town hosts as well as flea markets! They are almost always looking for vendors. Also, if you aren't aware of Etsy yet it is a website dedicated to all vintage and handmade crafts (if you are looking to sell nation wide) :) Happy selling!
Gyms and studios where hoop classes are taught (and in your own classes, of course)
Coffee houses and bars that have enough space for hooping.
At hoop jams that you run
School fetes and family festivals
Charity fundraisers (donate a percentage of sales to the charity)