I saw some greedy GSM selling something for 100k... but the cost of making it just only 20k or less if you farm item yourself.
So and try to stay close to their price by set it to 99,999 gil and go to bed.

Next morning I login and check my items all of them still here and that guy cut the price for 1 gil again!
The battle keep on like this for 1-2 days and the 3rd day I can't stand with this idiot anymore so i cut the price by half to 49k... and he didnt follow, and I can sell all my stuffs :P

I think it's not only for cutter... it demand and supply.
If you set price too high, no one willing to buy that piece of crap.
If you set too low, you have low profit.
If you not greedy and set reasonable margin, ppl will buy it and when they buy all from me, the next guys that price higher than me will have a chance to sell their item too!

The guy I mentioned I think he check the price of his item and adjust it more than 5 times a day =='