By Ana Nicolaci da Costa and Denny Thomas

LONDON/SYDNEY (Reuters) - Fears that a possible U.S. recession would rock the rest of the world and cost jobs intensified on Tuesday for small investors left counting the cost to pensions and savings from sliding stock markets.

Hundreds of billions of dollars of value has been wiped from world share markets in two days of volatile trade that have seen some of the most dramatic declines since just after the Sept 11 attacks in 2001.

The steep drops underline intense concern over soaring food and fuel costs, record levels of personal debt and faltering job security.

"It's frightening," said Paul Henderson, a 54-year-old manager of a clothing store in Fleet Street.

He said business was already trailing off and customers were increasingly using cash instead of credit cards -- implying lower-value purchases.

A hit to spending was also on the mind of a bartender in a Frankfurt pub near the city's wealthy banking district.

"If the economy turns worse maybe people here will not drink so much," said the Cuban-born bartender who asked not to be identified as she is officially unemployed.

Surprisingly, many Americans were more optimistic. Some saw falling stock or commodity prices as a buying opportunity, while others were grateful for the Federal Reserve's surprise slashing of U.S. interest rates on Tuesday, which could translate into cheaper car and home loans.