Billboard Space
For the financing and the continuing support of TMP Mod, I suggest giving all Virtual Trucking Companies the option to rent Billboards space for advertisement. Such rental space can help support TMP servers and assure a continuing interest to play the Multiplayer version of the game. VTCs would be giving the option to select the cities and locations and a price range depending on the amount of billboards they wish to rent.
Example: 1 city 3 Billboard $5.00 a month, 2 city 6 billboards $7.00 a month, etc....
The reason for this is so TMP has the financial support needed to keep the servers running and implement future things and the ability for any VTC to promote their company.