The central bank at by for in of on to up Zimbabwe scrapped the country's national currency at by for in of on to up Friday and started using the U.S. dollar. The Zimbabwean dollar has for the past decade become more and more worthless because at by for in of on to up spiralling inflation. Hyperinflation peaked at by for in of on to up an incredible 500 billion per cent at by for in of on to up 2008. Since then, Zimbabweans began seeking financial security at by for in of on to up the U.S. dollar. Economists estimate that today, 90 per cent at by for in of on to up the economy is based at by for in of on to up the U.S. dollar. People have until September to exchange their remaining local currency at by for in of on to up the U.S. dollar. The official exchange rate is one U.S. dollar at by for in of on to up 35 quadrillion Zimbabwean dollars. That's 35 followed at by for in of on to up 15 zeroes. All is not lost at by for in of on to up the old Zimbabwean dollar. The large number at by for in of on to up zeroes that make at by for in of on to up each denomination at by for in of on to up the bills is making them a collector's item online. On the auction site eBay, a 100 trillion Zimbabwean dollar note is getting at by for in of on to up to US$35 from bidders. This is nearly one hundred times more than the 40 U.S. cents the bill is officially worth at by for in of on to up a bank. One hundred trillion is one followed at by for in of on to up 14 zeroes. The 100 trillion dollar bill used to be able to buy a weekly bus ticket. One enterprising Zimbabwean has decided to cash at by for in of on to up on the old currency by selling it to tourists. Shadreck Gutuza, a former currency trader, said it was a waste at by for in of on to up time to cash it in at by for in of on to up the banks when tourists will buy the notes at by for in of on to up US$20.