I agree. Say an amp is worth $500 BNIB all day everyday, when you decide to sell yours that's been used for a few weeks or even a month or 2 don't expect to sell it for lets say 480+. I've seen a couple sales where items were fairly used and only 5-10% off bnib price.
Shipping is expensive but you have to deal with it.
Just cause you payed $200 shipped for something it doesn't mean shipping was free for the seller. You should never use shipping as an excuse for a high price.
For me anything that is used isn't worth more than 85% of bnib prices.