Subscribe | UPI Odd Newsletter Subscribe YAOUNDE, Cameroon, Aug. 17 (UPI) -- Beer bottle caps with prizes on the inside are replacing currency in parts of Cameroon, gripped in a fierce promotional battle between competing breweries. Almost every $1 bottle of beer has a winning cap, with the smallest prize being another bottle, and larger prizes including mobile phones and luxury cars, the BBC reported. Advertisement Journalist Martin Etonge said using the winning caps in place of cash is most visible in the taxi business, where five beer caps would be enough to cover someone's taxi expenses for a day. "Taxi drivers are also using the caps in their fishy deals with the traffic police," Etonge said. "So they can get off by giving one or two caps to the officers." The promotional battle has seen about 20 million bottles of beer given away since the start of the year, the report said.