Hi OSBot,
I've lately noticed this problem - and I am also sure many people have. New gold seller's just pop up and start controlling the market by offering gold for 0.20$ lower than other people around. This has caused the gold selling price to go down from 2.2$ to 1.75-1.80$ (if you are lucky, you will get 1.90-2.00$) within a month or so. It is very very hard to sell gold for above 1.90$ tho. This is only possible because people are willing to sell their gold literally for price of a last years potato.
I am sure gambling sites affect ALOT on this - but this is also about botters, the gold farmers. People are willing to sell their gold for 1.75$ for some reason. So - to stabilise the market, do not sell gold under 1.90$.
Just to mention - word competitive does not mean that new people trying to get in the market should push the current selling price down by 0.10 - 0.20 - This will only cause the market to crash, as new gold sellers are popping up like mushrooms in the forest.