Snoring afflicts about half of the adult population. Snoring is caused by an obstructed or narrowed air passage. Here’s a good article on Mayoclinic.com.
Two ways to stop snoring are to use an oral appliance or opt for a surgical procedure.
Since surgical procedures are not available on eBay, let’s look at oral appliances. 
An oral appliance is a mouthpiece that holds your tongue and soft palate in the front of your mouth to keep your air passage open. They go for $15 to $40 on eBay.
Here are the most purchased snoring aids on eBay:
