Honda (and Yamaha) has set pricing and don't allow much discounting. I have used Honda generators for years on construction sites and have found them worth the price for their durability and repair parts availability.
However if I were buying a generator for occasional use I would take a close look at the Champion generators. My FIL bought one to use at his barn, at the time the best price was from Tractor Supply. Champion has built themselves a decent reputation of a lot of bang for the buck. There are also several online sales places, like Generators Direct that quite often have good pricing.
Don't have a Costco nearby so no clue what they have.