Groupon offered onions for 9 rupees, or about 15 cents, per kilogram. The Indian staple -- one of the country's most-consumed commodities -- can now cost up to 100 rupees per kilogram across the country.
On Thursday, Groupon sold 3,000 kilograms of onions, or just over 6,600 pounds, in just 44 minutes, causing the website to crash. The site continued the sale on Friday and sold another 8,000 kilograms before selling out.
Comparing the onions to caviar and diamonds, the website joked that "people haven't experienced onions in a long, long time."
"We wanted to sell it at a price that most of us have completely forgotten," said Anur Warikoo, chief executive of Groupon in India. "This kind of onion price was last seen in 1999."
The average price of a kilogram of onions has more than tripled in the past two months due to supply shortages, inflation and a depreciating rupee.