At point of sell there is agreement. A contract ... when a contract is struck the item/service is sold.
People will bargain and they will use all the emotional, rational and crazy tools they can to drive a price down.
However, others will pay more for items of uniqueness and value. They may bid for it. That is the best to drive your prices higher, do bids rather than straight sells.
Ask the people how much they are willing to pay for it. If the items are going fast, then there is no reason to discount, but if the item is a hard sell then bring it down, because it means the value you give to it is not the same as the value given to it by the broader society.
Muslim brother discount is a valid argument to use, because if you please them they can pray for you, but being the seller the ultimate control for the final sell is in your hands so their barginaing is of no use, because you know what price it should be.
When I did market I had in my mind three bandings of price.
Band 1 - At Cost = Sold to incite further purchase
Band 2 - At ~30% mark-up = standard rate, but no prices written down
Band 3 - At double cost = with items that I know would sell I put the prices on them, and for those items that would require some bartering I left unpriced, but started the pricing of the item at double working down to about 30% over.
Some people show enthusiasm, some are regulars, some are trying to pull a fast one. When anyone who you think is pushing it ... make a different offer based on the other bandings and compare your products or offer a conditional discount and things should work out inshaAllah.
^Yeah, women do that. Not just with muslims, but any shop retailers they can haggle with LOL, its in their nature to bargain the shopkeepers brains out