At a recent game a player shared this excellent resource on potion cost list. The DM’s Guide has a large range for potion cost that really isn’t that helpful. I think this source is more closely aligned to the potion information in Xanathar’s Guide. Anyway, I thought I would share this excellent source: blackcitadelrpg.com/potion-cost-list-5e

I actually created a similar table for a some unique potions for a recent game as well.