If you want stone fast check out ebay and windmillhill is her screen name also Curt is selling some good rock Curts Chert, you can get through to him via flintnappers.com or paleoplanet, He is very reliable and always have good rock for a good price, Then you have Neolithics.com with Craig ratzat...another good man with tons of rock. If you live in an area where there might be knappable material you should just check into it you may find what you are looking for on your own. I just located a huge pile of slag glass, I once found a few pieces a few years ago and I found the source from where it came from...it isnt flint but it will make nice blades and points! So I hope that helps you some. If you need more info or help email me I will be glad to help.
Russ