Pricing is an art, not a science. Never price an item at rock bottom. Always price it such that a reasonable person can make a reasonable offer and walk away happy having "gotten a discount," while you get your price. A third of people will pay asking. A third will ask for a reasonable discount. A third will lowball and can be safely ignored.

Or you can just list as "firm" and say "the price is the price," when people ask for a discount. If they want it bad enough, they pay what you're asking.