Music store boss Andrew Obal has been left sick as a parrot because of England's World Cup success.
Andrew dreamed up a money-making offer giving customers a 20 per cent discount with an extra five per cent off each time Beckham and co win a match.
But the plan has turned into an own goal - and will soon be costing him a small fortune.
At the moment, the offer at Music World in Worthing stands at 25 per cent off all stock.
As England marched on after today's draw against Nigeria today, Andrew said he might as well be paying customers to take home musical instruments.
Bargain-hunting musicians flooded the shop after the Argentina match and saved thousands of pounds thanks to David Beckham's penalty.
If England get through to the semi-finals, it will cost Andrew a small fortune when the discount reaches 50 per cent.
He said: "I want England to do well in the World Cup but I'm being skinned because of that Sven-Goran Eriksson."
A huge football supporter, he decided to run the promotion when it looked doubtful England would qualify last year.
Little did he know what lay ahead.
Andrew said: "It was horrible watching the Argentina match. I felt like I was betting against my own team. One minute I was shouting 'Go on England' and the next I was willing them to lose.
"The next day the shop was chaos. Usually, the most you ever get off such instruments, even on the internet or by mail order, is 15 per cent."
On Saturday, he sold more than 30 guitars, many of which were prestigious Fender models, costing £500 to £800 before discount. Other bargains included five digital pianos, reduced from up to £1,500 to about £1,100.
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