A gift card fit for a Queen? Picture: Max Mumby/Indigo/Getty

The 90-year-old monarch was snapped laughing in delight at her prize of a £50 ($100) gift card for supermarket chain Tesco after her horse won at the races on Thursday.

The four-day Royal Windsor horseshow, held in the grounds of Windsor castle, was one of the main celebrations for the Queen’s 90th birthday.

The Queen snaffled the voucher after her horse, 14-year-old gelding Barber’s Shop, won the Tattersalls & RoR Thoroughbred Ridden Show on day two of the event, The Times reported.

She also won £70 ($140) prize money and a voucher for a jacket from a racehorse charity.

“She loves winning, absolutely loves it,” a source at the show told the paper. “She laughed. She opened the envelope, and it was Tesco vouchers — it must have topped her day off.”

The top prize for winning first past the post at the derby is £800,000 ($1.58 million).

As The Guardian pointed out, it’s unlikely the Queen ever eats anything from Tesco as the company does not appear on the list of firms with royal warrants.

The royal family spends about £25,000 ($50,000) a week on food and drink, according to publicly available accounts of the sovereign grant.

In 2014-15, British taxpayers funded the royals to the tune of £37.9 million ($74.8 million).

Queen Elizabeth II laughs as she receives a Tesco gift card after her horse Barber's Shop wins at the Royal Windsor Horse Show. Picture: Max Mumby/Indigo/GettySource:Getty Images