Finding a location is actually one of the easier parts of starting your camps. There's really a lot of options. Let me give you some examples: churches, libraries, restaurant banquet rooms, party rooms at businesses, hotels, dance studios, karate studios, retail stores that focus on children, fitness gyms, YMCA's, etc. Basically, you just need a room. A room big enough for 10 to 12 children to move around and play and have a great time and a bathroom (very important). You will need access to a table that will sit all your students (sometimes I bring the table myself), but most of these facilities have tables and chairs.
Why is it easy to find a space? Well, when a business decides to host your etiquette camp, they are increasing the traffic into their place of business. People who might not ever visit their facility, now will. It's also very nostalgic to host such a community event as an etiquette camp for children. You will be advertising their place of business, as you advertise the camp.
I would suggest you visit these places first, to make sure their facility is appropriate. Your attitude, dress and demeanor will send a message to the owner of what type of activity you want to offer. Be professional, grateful and excited and your enthusiasm will "rub off" on the facility owner. I usually use the statement, "My business is looking for just the right place to host our summer camps (or other camps), which are hugely popular and always in high demand. Would it help your business to have some unexpected traffic come in and become familiar with your facility (or place of business)." I also request sometimes for the facility to offer a coupon that I can give my parents to ensure that they not only visit, but use their facility. It's a win, win opportunity for both of us.