Also talk to your restaurant supply house about toppings such as Mustard and Relish. Purchasing these in bulk will save you a fortune. When you have it all together you can sit down and calculate your cost for a fully topped hot Dog and a plain Hot Dog. Your average cost will end up right around the middle. Now look into Soda prices.
Cans are the easiest to deal with.
You now should have a good picture of what your costs will be. Your next step is to look around at other vendors selling in your area. Make a note of their prices. This will give you an idea of what the market will bear. Set your prices based on your cost and what the market will bear.