• Aldi launched free "Blind Boxes" featuring mystery grocery items for budget-savvy shoppers.
• From June 22-25, Aldi will release themed boxes featuring protein and fiber products.
• The giveaway taps into consumer trends for budget-friendly and nutritious food options.

Aldi is betting that shoppers' love of mystery boxes extends to the grocery aisle.

The discount grocer, known for its low prices and private-label products, announced Monday that it will give away free "Aldi Blind Boxes" for four days, with a limited number of mystery grocery packages available daily through AldiBlindBox.com.

A different themed box will drop each day from June 22 through June 25 at noon ET, and shoppers can claim one while supplies last.

The giveaway arrives as many Americans remain focused on stretching grocery budgets while also seeking foods that align with popular nutrition trends. Aldi's four themes include protein, fiber, and snack products alongside a Mystery Blind Box, and will include items such as meats and fresh produce, snacks, cheeses, and pantry staples.

The promotion also taps into the popularity of mystery-box shopping, which has fueled demand for surprise collectibles, beauty products, and other limited-time retail drops.

"Our shoppers come to ALDI for value, but they also come for discovery," Bridget Kozlowski, Aldi's director of communications, said in a statement. "People love the thrill of discovering something new here."

To get a box, shoppers must visit AldiBlindBox.com when each day's giveaway opens and submit shipping information, according to the FAQ. Aldi said it will reveal each day's theme on its Instagram account.

The catch: The boxes are first-come, first-served — and once they're gone, they're gone.

Representatives for Aldi did not immediately respond to a request for comment from Business Insider about the supply of boxes that would be included in the giveaway or whether the promotion might return later.