What's the best and cheapest way to migrate data from a Macbook Mid 2010 to a iMac Late 2009

My 13' mid 2010 white unibody Macbook running OS X Yosemite has just recently broken down and can't turn on so I went out and bought a used 24' iMac 2009 running the latest OS X Yosemite.

Im thinking of purchasing an external HD and migrating data from my Macbook onto it and then transfer to my iMac to save money on repairing the Macbook.

or

If I repair my Macbook how simple will it be to migrate data straight to my iMac