Well, what dollar amount would be comfortable to you?
20% = $30
18% = $27
15% = $22.50
10% = $15
0% = $0
Standard tipping in a restaurant is 15%-20%, 15% being quite obviously the low end. Diners who do not have a hard time leaving $22.50 (in the example above) might consider a meal ranging in value from $112.50 to $125.