Seems people will google the gear find the lowest price online, not account for the shipping or tax and try and beat the guy up on the price. If you figure you are saving 10% off of retail, saving 6 1/2 ish % sales tax and shipping for gear that was only used a time or two,
Used equipment is only worth what someone else is going to pay. I’ve sold off my used equipment on and off for almost 40 years. Stuff that still had tags on it sold cheap because of limited buyers and worthless stuff sold for stupid money.
As for shipping and tax, has no bearing on value. In today’s world we have vast competition amongst retailers and many broker shipping deals that make it near free or minuscule in cost. Many online retailers don’t collect a tax.
Also keep in mind sale prices and model changes. This can reduce a new product to 60 or 40% of original price. I can’t tell you how many times I see someone advertise a used item for more than what I see it on sale for. Sounds cold hearted, but if you pay list price and then want to sell it, expect a major loss. The buyer of used goods is very happy to let you eat the difference