Belinda's stock portfolio was worth $1,500 at the beginning of the year. The prices of her stocks fell in the first, second, and third quarters, reducing the value of her portfolio by $124, $145, and $55, respectively. What is the value of Belinda's portfolio now, in dollars?

The value of Belinda's stocks fell a total of $124 + $145 + $55 = $<<124+145+55=324>>324.

Thus, the value of Belinda's stock portfolio is now $1,500 - $324 = $<<1500-324=1176>>1176. Answer: \boxed{1176}.