BELGRADE, Yugoslavia (AP) _ A shopper waited in line to buy a sandwich, then walked away empty-handed. A taxi driver shrugged in resignation as he turned down a fare with enough money for 10 rides.

No change, no purchase, no service in a country where there are large bills in abundance, but an acute shortage of small bills and coins thanks to a confusing currency switch.

After years in and out of hyperinflation, Yugoslavs are accustomed to frequent currency changes. But this time, they say, the chaos is unparalleled.

''It's a complete disaster,'' said kiosk salesman Aleksander Vrankovic. ''I have no change, they (customers) have no change. There are piles of old magazines here because I can't sell them.''

The newest currency was introduced July 1, a day after the government devalued the Yugoslav dinar by 84 percent as a result of a steep economic decline resulting from sanctions imposed by the United Nations.

Inflation in June reached a record 102 percent for the month and about 100,000 workers have been laid off or sent on leave since the United Nations imposed trade sanctions on Serbian-dominated Yugoslavia on May 30. The West has blamed Serbia for fomenting violence in Croatia and Bosnia-Herzegovina.

The exchange rate was changed from 32 dinars to the dollar to 200 dinars to the dollar and a zero was erased from the currency to make computations easier.

On the street before devaluation the dollar fetched about 2,000 dinars. Now it is worth a little more than 200.

Thus, 5,000 old dinars became 500 new, and so on. New bills carry the same pictures as the old ones the government was cranking out to keep up with hyperinflation, but the color is different and the bills are slightly larger.

It was the fourth time a new denomination system has been introduced in as many years.

The independent daily Borba reported that officials were blaming each other for the resulting confusion, and that Serbian Premier Radoman Bozovic had proposed setting up a state commission to investigate who was responsible for the apparent miscalculation of how much of various denominations were needed.

The opposition Democratic Party called for the resignation of Finance Minister Jovan Zebic.

Shoppers buy extras so they can use large bills. Stores are giving change in the form of matches, chewing gum or even toothbrushes.

''Every day, I buy something I don't use,'' said Branka Tadic, weighed down with shopping bags. ''I have a pile of matches. I buy two yogurts instead of one. I have chocolates I don't need.''

But Bojana Simonovic was resigned to not buying a sandwich. ''If they don't have change, I won't buy anything,'' she said.

Further confusion is caused by the similarity of the old and new bills.

The Politika daily reported a post office cashier in the town of Valjevo, about 55 miles southwest of Belgrade, handed out new 5,000 dinar notes - equivalent to 50,000 old dinars - in exchange for old 5,000 dinar notes. The losses totaled the equivalent of $3,300.