I have long collected bits and pieces of Michigan memorabilia through numerous travels across the state. One thing that I never fail to grab is the new map issued each year by MDOT. Probably the most popular cover in recent years is the 2007 map featuring the 50th Anniversary of the Mackinac Bridge. Michigan maps issued by gas stations have become even more of a collector's item. Old Shell, Mobil, and other gas stations used to produce maps as an added benefit to travelers, but even more importantly as an advertising tool. The practice was discontinued just about the same time as Full Service due to increased production costs.
For more information on vintage Michigan maps you can purchase - Collecting Vintage Michigan Maps