Mad thing
GO Money Changer, pounds 7.99

The makers have put a standard 10-a-penny calculator chip inside a red plastic case, and charge pounds 7.99 for it. I would like to tell you how much that is in Franch francs or Greek drachmas, but the machine only converts in one direction. Its timing is good; no longer can we rely upon Fr10 to pounds 1, and dividing everything by 7.50 is a pain in every sense. Programming the thing is a problem: despite a degree in mathematics and two sets of instructions, it took me three goes. I would give 799 lire for it (32p), or even DM7.99 (pounds 3.50), but no more.

Simon Calder