Buying an over-the-counter mouth guard can cost as little as $15. However, more well-known products can cost hundreds of dollars. Nonetheless, the price is much higher if you choose to go through the dentist and have your mouthpiece molded by professionals. The regular dental visits, modifications, and the mouth guard itself can go anywhere from $1,800 to $2,000. Though, if you find a good over-the-counter mouth guard for sleep apnea that works for you, you don’t have to spend this much. Anyway, there are manufacturers now that have your mouthpiece molded by professionals. They send you an impression kit, and all you need to do is send them back an impression of your teeth using a prepaid return shipping label. Then, after a few days, you get the custom-fitted mouthpiece that was created just for you.