The easiest way to find local suppliers is to go to the product's brand name manufacturer's website and use their "Dealer Locator", "Where to buy", or similar named tool to find the nearest distributor. Yeah you have to do it with each separate product but the odds of finding one that carries all you want is slim to none anyway.

Example: Azomite lists 4 distributors in Indiana. See link below.

Which/what phosphate?

Around here most any large nursery carries 50 lb. bags of greensand

Dave

Here is a link that might be useful: Indiana Azomite Distributors

I'm just north of Indy and there are many feed mills that sell all sorts of things. For greensand I order from amazon.com. A 50# bag was $25 with shipping. The local feed mill will order it on request at a higher price. Azomite is a common feed additive in pellet form. Not sure what you are looking for exactly but a lot of organic fertilizers are feed items.