The couple, who previously lived in Rye, East Sussex, worked 11-hour days and sought a 'slower pace of life', leading them to move to Chiang Mai, Thailand, in September.
The staff charged the 26-year-old customer, who was visiting alone, an overpriced 20,000 baht (£460) for his drinks at the Diamond Karaoke Bar in Chiang Mai, on Wednesday.
Shao Chun Chen, 39, pays about $460 a month in rent for his luxury condo in Chiang Mai, Thailand — one-fifth of what he paid for his unit in Singapore.
Tourists Amina @amonthego and Alex @alexwandersyt, from the UK, couldn't hide their shock after stumbling across the gimmick at Chiang Mai Breakfast World.