Bit of a niche product here as you need a darkroom and chemicals to use it. This will NOT work in an inkjet printer. Cheapest I can see with stock elsewhere is Silverprint @ £43.39 a pack. Prices on some photo paper seem to be like a yo yo on Amazon.
If you ever see any on Amazon Warehouse, advice based on my experience is don't bother. It seems like they're basically reselling paper someone bought, opened in daylight while unsuccessfully trying to use it in their inkjet, and sent it back. I only got lucky as the box I bought had 4 separate bags, only one had been opened, and Amazon part refunded when I contacted them.