I'm a dummy. I forgot to mention my friend Jim at BC Bonsai in Wheaton IL. They have a small shop at their home, its a part time business, and they have a more than 10 acre growing out field a few miles to the south of their home. They have hundreds of pre-bonsai, nursery stock and all kinds of stuff. And their prices tend to be quite reasonable.
bonsai,supplies,lessons
www.bcbonsai.com
They are very likely to have a BC or two laying around. Tell Jim I sent you. Oh, the BC Bonsai name is from the first letter of Jim's last name and his wife's last name, I keep blanking out on what her first name is. I haven't seen them since before Covid.
One more option.
Bonsai Show, August 19 thru Aug 21 at Chicago Botanic Garden. The CBG is at Lake - Cook Road and Highway 41 in Glencoe IL. The CBG is run jointly by Chicago Park District and Cook County. As a result I have met both Tony Preckwinkle and Laurie Lightfoot at shows at the CBG, as they are the "womens whats in charge". It is startling to bump into them, usually you notice their bodyguards first. Tony is really very friendly, we had a 10 minute conversation the first time I met her. Must have been a slow news day.
The Bonsai Show is put on by the Midwest Bonsai Society, it will have 100's of exhibition trees, at least 15 to 20 vendors from all over the country, the vendors will bring trees nursery stock and there is always an abundance of seedling bald cypress at the August show. Superfly bonsai will be there with tools. Some vendors will have pumice, akadama and other substrates for sale. And of course POTS. You can meet Sarah Raynor in person, and buy a pot from her. I buy a pot from Sarah every year, usually just one, I probably have 35 or 40 Sarah Raynor pots, most just sit on the shelf looking nice. But I like her style. She's not all that talkative, but it is always fun to see what she brings, each year her pots evolve, different in styles, textures and glazes. Each year a different clay body, it is fun seeing the changes over time. Linda Ippel might be there, a Michigan potter, there are usually 4 or more potters, Byron Merrick is a bonsai potter from Louisiana that you MUST take a look at his offerings. Very useable pots. Most of my pots from Byron have trees in them. (not just sitting on a shelf). So get to the show Aug 19 to 21