It will be cheaper to find a manufacturer outside of the US, but only if you are ordering a large volume. Otherwise you'll spend more on shipping, customs and set up. One thing you might do first is source something closer to home. If you have an idea of the materials you want your flip flop to be made out of, you should look for a trade association dealing with that area. Contact them, tell them what you are looking for and they can guide you to one or two member companies that might be able to help. I'd start by making a few samples to determine if you can sell them prior to moving it overseas.

