There’s a special type of Costco stores called Costco Business Center. They’re designed for businesses, but you can shop there with a regular Costco membership. Not sure how many there are, but there’s three near me in the San Francisco Bay Area: South San Francisco, Hayward, and San Jose.

They have a lot of restaurant supplies for cheap. One example is a two pack of Tramontina ProLine knifes for $20: https://www.costcobusinessdelivery.com/tramontina-proline-8-and-10-cooks-knives-commercial-grade-2-ct.product.100227891.html (online price; it might be cheaper in store).

It’s a great place to get mixing bowls too - they have stainless steel mixing bowls for $2-3.