I love rubber bands. They are so versatile and are excellent tools. Unfortunately I almost never have the right size. The type available from Walmart and other local stores are usually extremely low quality. They stretch permantly which is a sign of low rubber content.

Anyway, I did an extensive search last summer for a place that sells sample packs. I found this company that sells packs of a one ounce of a dozen different sizes. Each size is individually boxed so that you know what size you're actually using. This is very helpful when you find you use a lot of a certain size and want to get more. At the time they had four different sample packs. I ordered all of them which gave me 48 different sizes. The total cost was about $25.00. It was money very well spent.

http://www.dykemarubberband.com/samples.php