WM is widely known to have almost the highest prices possible. Beyond that, if you were to begin producing toilet seats you would need a mold or another form of tooling. The tooling costs the same whether you sell 5 or 5 million. Most of the time I hear mold prices for injection molded plastic parts for instance at around $25k-$50k. If you have to spend that to produce a product you must include some portion of that cost in each part that you sell. The fewer you sell the more of that cost will be reflected in each part, driving the price up. There's also shipping. let's say it costs $10.00 to ship one toilet seat. If you only need a half a dozen you'll still pay quite a bit for each piece to be shipped. If you can order a pallet of toilet seats to sell you can bet that the shipping per item to the retailer will be much much less than what UPS charges to deliver one or six. Again the cost gets passed on to the lowly toilet seat. The same is true of any product. This is most evident in food prices. It costs a lot more per almond to harvest, shell, and roast one can of almonds by it's self than it does to harvest and process 1000 acres of almonds.
Almost everyone can beat almost every price at WM.