Does anyone know how to figure out the sellback value of a piece of Equipment that one doesn't own and can't find for sale in the Broker?

I specifically need to know the sellback value of a Level 55 Rare (blue border) Relic.

if you're on computer, hover your mouse over the item and check the bottom right corner of the info box (or just right click/click the item then the sitesell box to put it into the sitesell box and check the payout value)
This will of course only show the sitesell value not a broker value, but a lv55 rare equip isn't going to fetch that much more than that

Unfortunately, Scath, I don't have one of the items to hover my mouse arrow over, nor can I locate one.

Someone sent me a Level 55 (Rare) Relic as partial payment for something. This was just before midnight, and I didn't look at my Trades until after all my unsold items had appeared. Then I failed to notice that one of the items wasn't from the Admins but was from a player, and I just accepted them all and sold a bunch of the items back to the game.

Including the Relic in question.

The player doesn't remember the sitesell value. I'm trying to figure out how much gold credit to give them for the item, which would be its sitesell value.

I currently have 5 of those of varying types with different values: 583, 620, 626, 628, and 655.

once again, what I get for answering questions when I have just woken up, brain does not register many things when having stuff placed in front of it. like words. and names.
Sub-60 equips are a bit awkward because the stats can vary a little per piece and the sell value's based on that. Averaging the prices from Athenaolympia's gives 622.4, so maybe 622 gold if you wanna go averages, 655 if you wanna go upper end.