All i'm proposing is for the OP to advise the original (or current) price the retailer/manufacturer (he/she is using) sells the item for together with the GB price in order to see the discounted rate at 1st glance.
i think its apparent to the general population we can "all do our own research"
but having a benchmark to work with i think would be a good idea.
TBH in general, if you do your research you can get your items cheaper, but i just think it would be a good element to have as standard when posting GBs
This is only my view...