Well, I didn't exactly make her a bad bass player overall, just with the fictional Deja Vu's music. Secondly, $150 was Kevin's pay for filling in. As a session musician already, Alex would have gotten her standard pay. Which, when I looked it up was a pretty wide range, 25k-100k or more. So, $150 per day for 260 days is $39,000. Closer to the low end of that scale. However, there are a lot of differing opinions on the Internet (Really?), but that amount seemed reasonable for an amateur filling in.
It's not listed anywhere because it's sold out. TicketMaster took it off its site. Keep checking StubHub and similar, maybe you'll get lucky. (But don't hold your breath.) Besides, I wasn't lying to you. I believe this is called fiction and I can say whatever I want!