if the buyer agree wit the term n condition which is set by the seller and have paid for it,which means buyer have agree with the amount which is agree by both rite!!
doesnt means tht even the seller sold it cheaper to other buyer which it say its unfair to u as u dont make nego til tht amount which is other buyer did  right!!every buyer n seller can nego until the transaction is paid right!!!
tht just my opinion..

SSD and Hdd Price keep changing everyday/ week
same like tesco price keep changing. once u deal with this price, then this is the deal.

can discuss to reduce the price. but when u agree to deal with the seller with the first price. then that is the deal ! no such thing as when price diferent then deal differnet price. wat if the price higher ?

Case Study 3:
a customer bought a media player (R1055) then he go flash the firmware (other brand !  ) within 7 days he bought, not sure what he not satisfy with the player but there is nothing to improve for a realtek 1055 player because no have networking feature and no IMS software support.
end up he ask his father come to my office to request one to one exchange because he brick his player. of coz we keep the player and exchange the PCB because we failed to recover it and request RM50 for the service charge. His father said the item still not exceed 7 days, should get one to one exchange and no any charge for the repair. then he said if buy from Tesco sure can get refund or exchange within 7 days.

* Yes product can be exchange / refund within 7 days with reasonable like faulty or quality problem. If user brick the unit by flash with other firmware. this is their own risk, what we can do is help to recover or exchange the PCB and charge customer. Think from the seller side, we need to send back to manufacture at China with the cost just because you flash the wrong firmware or DIY the Player.