At 8:05, does he really say "Hey, it's gonna be $500"?
I think so, yes. He says "it's gonna" very fast, in the same way that I believe some AmE speakers say "Imma" for "I'm going to/I'm gonna". It has far fewer syllables when spoken than you would expect. I don't know if rushing "It's gonna" is common amongst AmE speakers but I think the subtitles are correct.
Note my corrections in the quote box. I think I mentioned to you before that you need to be careful with how you write timestamps. "8:5" means nothing. It's either "8:05" (eight minutes and five seconds) or "8:50" (eight minutes and fifty seconds). Just copy how it's written at the bottom of the video. When you play the video, you can clearly see how the times are written.