Make some very expensive items for late game, like placeable propane tanks from small (maybe1000gas) to the big propane containers (10k gas) so you have uses for all you collect later on. The propane tanks would be grand placeable explosions for fun too. Maybe like statues that are 10k metal or concrete too. Could go on and on, but propane would be grand. Just did a 7day at a farm, not seeing the propane before setting in and took out like 15 zombies with it.