Where to find cheap o-rings or a substitute?

I've been looking online for a few 14g o-rings, but cannot find any sites offering them cheaper than 3/4 dollars for 1-4 of them. Seeing as they'd cost a whopping 44 cents to mail, I don't want to pay more than a dollar or two for about 10 of them. Now if this option isn't feasible, does anyone know of a good replacement/substitute for them? Ideally clear since these are being used for retainers, but this isn't necessary as I can always just wear the retainer backwards. Please only answer if you are knowledgeable about body jewelry. Thanks.