I've also bought seeds from here.
http://www.gourmetseed.com/
Their packs range from 150 to 450 seeds. They have larger sizes. For example 10 grams( about 1/3 oz) is $10.75
My experience is that Sand Hill's packets tend to have more in them than they promise. The coyote tomato seed I bought had something like 200 seeds in it. I don't know how much it varies between packs and varieties.