Shoppers should compare similar products on sale now so they do not pay more for less, Bogomil Nikolov of the Bulgarian National Association "Active Consumers" told Bulgarian National Radio (BNR). He explained shrinkflation: the pack holds less product, while the price stays the same or goes up.

The term is new and appeared with the economic crisis. A maker cuts the weight, but the buyer looks at the shelf price, which does not change. The smaller amount goes unnoticed, while the price per kilo quietly rises.

"As consumers, we must learn to compare across, not down," Nikolov said.

He said shoppers should not check a price against last Thursday's, but against what rival products cost now. They should pick the best deal.

"This is the only weapon the consumer has, but it is very strong when everyone uses it," he added.

If people do not pay attention, do not pick and choose, and shop "with their eyes closed", the market will keep heading the same way, Nikolov warned.

There is also skimpflation, when firms cut the quality of a product or service to keep their business profitable. In practice, this means less money for staff pay or for materials.