Maybe get some other players and form a sort of trading group. For example, I am short 2 dozer exhausts, I could sell 2 blades or whatever and if you have extra exhausts you would sell them to me? I am budarosa II on this game, don't know how the friending process works here but it might be a way to keep playing without spending actual cash.
I would never do in-game purchases, if you aren't earning your items via game play, it seems like it would be just boring... Buy some of these, lay out a road and some houses and stuff, rinse, wash, repeat...
