The Spanish word 'barato' (meaning 'cheap') has an interesting journey from ancient Greek through Italian. It ultimately comes from the Greek word 'prattein', which meant 'to achieve' or 'to trade'. This evolved into the Italian word 'barattare', meaning 'to exchange' or 'to trade'. The word then entered Spanish as 'baratar' meaning 'to trade' or 'to buy cheaply', before finally becoming the modern Spanish adjective 'barato' meaning simply 'cheap'.

This semantic evolution makes intuitive sense - the concept of trading and bartering goods eventually became associated with getting things at a good price or cheaply, until the word settled on its current meaning focusing specifically on low cost.

The verb 'baratar' is an older, now less common Spanish word that's directly related to 'barato'. While 'barato' is the common adjective meaning 'cheap', 'baratar' was the verb meaning 'to trade' or 'to buy cheaply'.

While English doesn't have any common words directly related to 'barato', we do have some words that entered English through business and trade with similar meanings, such as 'barter' (to trade goods without using money). This comes from the same general family of trading-related words in medieval European languages, though it took a different path into English.