I recently had a chance to meet with two of the team members from Purple Cow Organics, and I really enjoyed the experience. While I can’t give a firm recommendation on their products until I’ve had a chance to use them, feedback from other growers in my area is highly positive. Their pricing on bulk soil appears to be very competitive. Might be worth checking out and I’m fairly sure they’d send samples to big operations (they gave us samples to try). They’re a local WI based company, here’s their site: https://www.purplecoworganics.com/ .
Disclaimer: I’m not affiliated with the company in any way beyond being a potential customer. No commissions, no kickbacks, I just think they seem like good people.