for an example if the item buyout price is 1 mirror, does that mean you have to give the guy mirror + divines as a fee or do you just pay divines and then the guy mirror the item and give it to you?

you have to bring the mirror + fee

damnnn ok ty

If you use the TFT discord their Mirror fees are insane ( Like 300+ DIvine for a fee ), I would check the Settlers Shop that Spycisushi and a few other people work on. They do no or low fee mirror items but they are generally like 1 tier off flawless so they "Settle"

And avoid shady ppl ofc