I also have the same problem. I started to find the game really interesting until I got to the point that I had no resources left but needed to exchange tokens for food and oil. I'm stuck there. There's nothing I can't do unless I get in crazy debts and the city becomes an extreme failure. One of my friends, he's also playing in Solo mode and happens to be in the same situation. Oh ya, for my Oil problem, I don't even have a check-mark to enable trading.lol
I strongly believe that we are playing an unfinished version of the SP mode. MC didn't take time to create the trading system for a SP, they just took the same they created for PO and decided to create the fictional Omnicorp and set up a trading rate of 4 for 1. As for the check mark, they come-up randomly, whenever the game feels like activating them. Sux that MC only wants our $$$
