I don't believe in the idea of "if you can't afford to tip, you can't afford to eat out", and I say that as someone who has been a server, and a busboy. I don't like the idea of "if you can't give me a tip, then you shouldn't be here".
That said, I do tip well. When it comes to eating out in a sit down restaurant (say like Applebees, or Cracker Barrel), I tip $5 for myself, and $1 for every friend with me, not counting what my friends might leave as a tip. I plan ahead for that.
When I order a pizza, the driver gets $3 if it's a small order, $5 if it's a larger order, $7 if it's a large order and it's raining, and $20 if it's any time during the week leading up to Christmas.
I've been tipped generously by small groups, and not at all by large groups (fuck you, Amway meeting. Also, fuck you Southern Baptist Church with your 20 goddamn kids). One time, a little old man tipped me 25 cents, and he patted me on the back and said I did a fine job. I thought it was adorable.