Of course, we’re assuming that since this scene is taking place in Australia, Thor is referring to the Australian dollar, the exchange rate with the American dollar would certainly be different.
To be fair, it’s possible the landlord could use the pumpkin, we’re not certain if Darryl has asked.
What is clear is that Thor is trying to put one over on his roommate, as he claims his Asgardian coins are all worth a “gazillion” human dollars.