Oh geez, I just realized that you can send a bunch to the build station at one time. I was stressing myself out trying to time everything totally perfectly. Phew.
I've been dying a lot in level one because I'm so paranoid about the money issue people keep mentioning. If the developer is afraid people will just grind early levels, why not do two things: 1. Make the levels re-playable. BUT 2. You only earn what you get above your "Most Money Earned" amount. So let's say I play and get $800. If I replay and get $1,000, I get $200. If I replay and get $1,000 again, I get nothing.
I beat the boss, but then I was left on my lawnmower with no one and no way out. It was sort of like the ending of the movie version of Silent Hill. I guess I'll just... drive around for a while.