ditto - also known as trying to make an excuse into a valid reason

DH delivered pizza for a few months (our regular place really needed someone, and he decided the extra income couldn't hurt).
the job was tip-based, and he received about $1 from each delivery fee.
the most he made for 4-5 hours work was about $30-40 (and there were ppl who requested him - he is very sociable

). the delivery ppl often would have to sit around, not making any money, just waiting for a delivery call during the week. what little money that came in was spent on gas (not counting "wear & tear" on car). a very few ppl tipped well (interestingly enough, lower income areas tended to tip better - high income were most likely to tip nothing....maybe being cheap is how they stay wealthy

).
that "job" cost us money.
so yes, if we get a pizza delivery (rarely), minimum tip is $5+. we may love bargains, but not at the expense of someone who is opting to work at anything, rather than sitting around, depending on unemployment.