I can tell this is old because the tip selection doesn't go up to 30%+.
Seriously, tipping is getting out of hand. I compromised by going above 15% to begin with, I'll be cold and dead in the ground before I go above 20% and I will die on this hill.
They often have no damn clue what they're selling and clearly just make up prices on the spot. I've flipped a few things for a 500%+ profit from the super-ultra-Jesus-ey thrift stores. Computer hardware in particular is something they just don't grasp the value of. If you ever need a managed switch or a spare monitor, check the thrift stores.