Depends on where you are. There are specialty wood dealers and saw mills scattered all over. Rockler and Woodcraft are two chains that carry some hardwoods. There are also mail-order suppliers if you live outside reasonable travel distance.

Even if you did find these woods at the big box stores, they are generally dressed to dimension and quite a bit more expensive than other suppliers.

You might check with woodworking clubs or cabinet shops around and see if they can tell you a couple of places to try.

Here is a link that might be useful: Woodfinder

Don't buy your "specialty " woods via the internet ! You're going to want to pick the wood yourself. The last thing you wanna do is buy wood from a place like Rockler or Woodcraft !
You need to open the phone book and find a lumber yard, not a place that sells plywood and trim to the homeowner and building contractor. You need a legitimate lumber yard. They are out there,do some research and you'll find one.

Regular lumberyards---not HD/Lowe's/Menards---sometimes sell hardwoods. There are also regional sawmills and dealers. Buying large amounts of any wood is basically the same---be it from a yard, mill, or the internet. Yo0u ask for a specified number of board feet and that is what you get---bulk. I do not know of any dealer that allows hand picking boards for large orders. The lumber yard where I buy my exotics has small amounts of selection---enough for face frames, for instance.

Look in the yellow pages under "hardwoods"; you should find at least one in any middle-size city, that specializes in these and -frequently - in exotic woods as well.

Wood broker, nice guy, can get you anything: Darwin.crawford@gmail.com. I think the business is Mississippi Wood Trader.

Around here, its Pittsford Lumber, or Bristol Valley Hardwoods, or a variety of other places. Auctions often have lumber. I bought some great cherry at one, splitting it with a friend, and the last auction I went to had another nice lot of it. I bought some splendid wide black walnut boards for a song from a small sawmill once.

Woodcraft sells hardwood, but it is NOT inexpensive. I've bought a couple of boxwood turning blanks from them. I have bought some nice handle blanks from Lee Valley for wood turning tools. They were quite reasonably priced at the time.

In general, avoid the box stores. Look in the yellow pages for hardwood suppliers and sawmills.

John