Best way to spend 300 donuts?

Frink's lab and Otto. Just like you've seen with the Teen, their jobs pay out 50% more so if you play a lot you can send them on 60 minute jobs and make a lot more money fairly quickly, plus Frink's lab pays out $105 every three hours and the bus pays $300 every 12 hours, both of which are also 50% more than the purple and white houses.