No.
You can sell countries for gold coins, and trade the gold coins for cash, at least in theory.
But there are conditions.
From the "cash payout" section:
As a Full Member you can in some cases request a cash payout.
- Your account must have at least 1,000.00 Gold Coins.
- Your last payment was more than 45 days ago.
- Your last payout was more than 30 days ago.
- You have at least one country.
- Your countries and enterprises are not expired.
- All your countries are at Game Level 3 or higher.
In other words, you can only get up to $25 per month from GC and only if it's been at least a month and a half since you paid them for subscription. Also, though I've never tried it, apparently W3C takes their time in getting payment to you...