not a good idea. We have propose the market in the past but I admit where is the fun if we can get all in just 1 click? Look by example the game Diablo 3 when he come out in 2012. With the Auction House make everyone rage. Speciafically because players was able to sell items for real money. Some have make over 50,000$ with just 1 or 2 items. Was a good idea on paper but not in real.
In many games however this work great but the problem is the multi account abuse. Like the game I have play in the past Dino RPG on firefox where you can buy stuffs with ticket.However the problem was you just need to have multi account and bingo. You can buy anything you want. Buy the special package who allow you to tranform tickets in gold. The abuse was huge.
In RR2 we all know the game is full of multi account,cheater,hacker,etc… so add a marker or whatever linked to this will make RR2 worst. Already the Pro league have bring a lots of cheater. A market will brake the game totally. Fun to have but in RR2 will make the game more worst