can someone tell me please where i collect the shrink crystals from

You have to purchase them with city cash.

great so thats a goal i wont be finishing why give us goals like this not everyone can use real cash for the game

Aside from purchasing extras for City Cash, you can also get some Shrink Crystals by completing the Shrink Ray goal line:

Goal 1 : Shrink Your City - 3x Shrink Crystals
Goal 2 : Small Improvements - 4x Shrink Crystals
Goal 3 : Micro Mission - 7x Shrink Crystals

Thankyou for your help