Can you explain how to solve this math problem: Gloria wants to buy the $129,000 mountain cabin that her friend Alfonso is selling. She only has $150 in cash. She intends to raise the remaining amount by selling her mature trees for lumber. She has 20 cypress trees, 600 pine trees, and 24 maple trees. She will get $100 for each cypress tree, $300 for a maple tree, and $200 per pine tree. After paying Alfonso for the cabin, how much money will Gloria have left?