Well, that was from the beginning of their second round of hyper-inflation. My friend Frank, who gave me the Z$1 bill, went back to Africa recently and returned with this from the same series of banknotes:
They've since then knocked off most of those zeroes and reissued the currency to begin their third round of hyper-inflation.
When money loses its value this quickly, it ceases to be money. Anyone with savings in their bank (from which they are allowed to take out roughly 20p a day) has pretty well nothing left. If you want to buy anything, then either you use US dollars (and hope no-one tells the police you have them) or you barter.
The "agro-cheque" name, by the way, is because the country is backing its currency with its land (the usual last resort of countries suffering hyper-inflation with no reserves left). It's intended to suggest "agriculture", although MMORPG players and 1970s-era boot boys will naturally consider "aggravation" the more appropriate root...