CJenkins is the best source of the best quality at the best price.
they offer everything from prepare-your-own to prepared yardage.
they're slow to ship if you order directly through their website. if you're in a hurry search for shops that carry their products.
http://www.cjenkinscompany.com/
i'm sure i haven't seen all of them, but the other brands i've looked at are beyond horribly, ridiculously expensive.