A common error: apostrophe in plural

In English, the majority of words form their plurals by adding -s.  
Do not use an apostrophe to make a noun plural.

As fruit and vegetable stalls often display this error, it has come to be known as the 'greengrocers' apostrophe'.   
 

2 melon's for a pound    (melons  )
1 kg of apple's for a dollar    (apples  ) 

This error occurs in many other places:

The correct spelling here is TAXIS.

 The correct spelling here is cameras.

SO, next time you write something in plural, think twice!