The Currency Exchange tab allows you to exchange your hard earned cash for Megabucks. Megabucks can be used to purchase Mega Tickets, which can substantially benefit your investments. They can also be used to Mars.
Once thing to note with the Currency Converter; currency rates are subject to serious inflation, and will fluctuate the more you exchange for Megabucks. While the first couple Megabucks will be relatively affordable, it will get progressively more and more difficult to afford the exchange rate for Megabucks.
Each planet will have a different Currency Exchange, so if one planet is becoming too expensive, switch to another and get your Mega Bucks there!