I agree that while it seems mercenary to talk about money when speaking to guy in bar, it helps prevent misunderstanding later on after off.
My personal stance is if no sex is involved, I only pay 2k and i always tell guy in advance. But once, I took a guy out from Good Boy bar to watch drag show at Stranger Bar and I forgot to tell him about my policy. After the show and as we parted ways outside soi 4, I gave him 2k but he said I must pay 2.5k. I paid him the 2.5k but I never offed him again.