If you think it's your turn to pay for dinner just pay, don't ask.
Tipping amounts
Occasion
Amount
Beggars
1 ß coins
Car parks/small restaurant
5 or 10 ß coins usually,
20 ß or even 100-500 ß if you feel rich
Weddings
200 ß from friends, 500+ ß from bosses
Religious events
100-200 ß
Religious fundraising
20 ß
Haggling: don't expect to get more than 30% off, usually you'll only get 10-20%
especially if you are a ½ÃÑè§ farang.
It gives you something to aim for though!