I have a consignment deal with Fred Segal, as well as a few local shops, and many online stores. Each one works a bit differently, so I start with my own contract, and make changes accordingly to the way they operate. Consignment can be tricky, as you don't want to be responsible for lost or damaged goods, and you want to be paid on time - either per sale or per month, depending on your price point. You might also look into dropshipping, which frees up your inventory but allows online retailers to sell in a consignment style manner. Lastly, we had a unique model, where we would allow consignors to order wholesale from our site if they didn't have the right size, color, or style in stock. Would love to talk to you more about this!
