Ask most prep centers what they charge and you get one number on a call. The fee sheet turns up later, with receiving, labelling, bagging and storage broken out separately. By the time you know your real cost per unit, your stock is already sitting in their building and moving it is expensive.
We built SellerNest the other way round. Every rate is published before you speak to anyone. Six volume bands, all visible. The add-ons that usually arrive as a surprise, storage past thirty days, oversize handling, bubble wrap, bundling and returns, are priced in public too.
That is the whole idea. You should be able to work out what your next shipment costs in about ten seconds, without handing over your email address first.