Most designers maintain that pirated versions of design classics are a form of forgery and they certainly don't offer the same quality as authorised reproductions.
They are, however, a great deal cheaper. You can buy a chair that looks very like the Egg chair for €950 from www.cadesign.ie or a close imitation Verner Panton classic for €250. Only design nerds will spot the difference.
Although it appears similar to Alvar Aalto's design classic, the Stool 60 – Ikea's four-legged Frosta stool (€11 from www.ikea.com) – lacks the elegant balance of the original.
Some enterprising hackers have modified the design by removing one of the legs and repositioning the others to make the stool more stable.
These upstanding 1950s' British button-back chairs (€737 from www.galapagosdesigns.com) were rescued from a golf club in Manchester, given a bit of a scrub, and inventively reupholstered with phoenix-patterned fabric.