Asking for the whole lot upfront is a big red flag for a scam. Someone I've been to a few times asked for £5 upfront by paypal the 1st time as I was a new client and they had had a few no-shows. I thought £5 hardly seems like a scam and paypal users can be traced fairly easily so I did it and it was legit. And had a nice meeting with them. Anyone asking for big amounts (especially a ton and a half) probably is trying to rip you off. Bank transfers are not as easily traced but while I've heard of cashapp I know very little about it so I'd be wary of it
Thanks for the heads up and glad you didn't get ripped off