For general AV supplies and electronic components, there are actually a handful of trade suppliers that have their prices open to the public. The catch is the minimum order quantities and handling charges, where the MoQ may be 10 to 100 depending on the item and the handling charge something like 5% to 10% if the total order value is under a certain amount.
The main example I can think of is CPC UK (link). When I worked for a computer shop roughly 10 years ago, I remember them trying to set up a trade account with CPC, only to discover that their prices were actually as displayed to the public, where as with most other stores there was a substantial difference between the trade and retail prices.
On the other hand, even when a trade supplier is open to the public, the service is very different to a retail shop. I would generally only order from CPC or another trade supplier if I planned buying 10 or more of certain components to get the cheaper handling fees or where a produce was substantially cheaper than Amazon or elsewhere with the handling fees taken in to account, e.g. cables and electronic components. Quite often I ended up having to return wrongly-picked items, unlike retail online stores where it is rare to get an incorrect item.