Where do you buy your plants?

What online companies are good sources for perenial plants like mint or comfrey? Most places seem to sell tiny plants at high prices.

Coe's Comfrey is a great place to buy. He sent me extra and is a really nice guy to work with. I can't remember where I bought my different kinds of mint plants, but you won't have to buy many. The stuff spreads like crazy.

I try not to. I'm a cheapskate and hate to pull out the wallet.

Mint is such an invasive that anyone who has it will be glad to let you come and "weed" their garden. There are many public spaces where you can take a cutting, or find plants that have gone to seed. There is a nice plum tree in the parking lot between TiresPlus and Pier One imports. A cutting from that tree is now growing in my front yard. There are many ornamental kales in the parking lot that Chick-Fil-A and KrispyKreme share. They are in flower now, but in another month, I will be helping to get rid of the "unsightly" stalks on them.

Another reason to collect locally is that local plants are further along to adapting to your local climate than nursery plants that could be trucked in from hundreds of miles away.

I'd also like to encourage plant-sharing among us permies here on the board. I've been trading plants and seeds with some folks here.

Lately I've been buying plants in the produce section of the grocery store, where they are very inexpensive; Turmeric, Taro, Ginger, Choko, Sweet Potato, Irish Potato

We get most everything through local (within a couple counties) plant and seed exchanges....herbs, brambles, fruit trees, shrubs and ornamentals....I buy some herb plants that are grown nearby just because I can't resist something new. Other than that we've only ordered a cherry tree from Starks one year and another year a male kiwi from Edible Landscaping to go with the female kiwi I had traded for.
If there aren't any plant exchanges near by, host one yourself...it's a great way to meet other gardeners and get a lot of locally grown things. It might take a few years for folks to work up to it but after awhile, for us anyway, folks had things potted up just for the exchange and grew some extra things from seed to trade. https://permies.com/t/16133/permaculture/host-local-plant-exchange-source

Does anyone know a good place to order Lemon Verbena? I can't seem to find it locally. Thanks.

Thanks! I just placed an order with Coes for comfrey. I found some free mint.

On the subject of the herb layer, super local [as in the woods nar your place, or a yard near your place, etc etc etc] is best.

As for trees and shrubs- living in Western Washington I buy most of my plant from Burntridge Nursery, with a few alternatives purchased from Raintree Nursery and Onegreenworld.

In Missouri Starkbros is probably an excellent resource for you.