What is wrong with someone who has worked hard, earned money and is
lucky enough to find credits for sale at 2000 gold each, reselling them
for a profit, if they so desire? Hard work has it's rewards, work hard,
earn money, and if your not happy with credits at 2700 gold, wait. They
might go down in price, they might go up, who know's. That's what a FREE
market is all about. (note the word free in capital letters to emphasize
it's importance). A capitalist system rewards endeavour, well, most
times. What you are suggesting is communism. A system where hard work is
not rewarded, where people can sit at Dockhand Square, Fish Street or
who knows where and bitch and moan to anyone who wanders by that credits
are just too damn expensive these days and how much better things were
when they were young instead of getting up and killing a few extra rats
and making the extra money they need.
If people are buying huge amounts of city credits and reselling them for
a profit is going on, it's not the fault of the credit market. Even if
this is as huge a problem as you believe it to be, what is wrong with
doing that anyway? I have a moral objection to it, but if my city was
prepared to sell me credits at 2000 gold I would consider those to be my
credits, and no one, no matter how loudly they complained would be able
to tell me I couldn't do what I felt like with MY credits (note
capitalization again--see above).
So, basically, if you think the current price for credits is too high,
don't buy them or stop moaning for just long enough to go kill a few
extra rats.

Penned by my hand on the 25th of Miraman, in the year 336 AF.