Foam board for buildings
Wood dowel rods, wood hobby sticks for Windows
Fodder pars and prices
Cars are cheap plastic toy cars I found online

I always wanted to do a city playset to display my figures. I made 4 buildings, including a movie theater, firehouse, apartments, and diner. I added light posts and wrecked cars to add more effects. Figures can fit inside Windows on actual floors and on rooftops. It's a perfect scene of Cobra troops invading a city; tanks, blown up cars, guys repelling from helicopters and lots of firepower. Not to mention the GI Joes they're trying to stop the evil Cobra forces.