Go Big or Go Home - Music Lessons

The kids and I have been kicking around the idea of starting some music lessons for them. I think it would be great for their creative side, their intellectual development, and just fun in general.  I've been suggesting the piano or the guitar as some possible starting points, but Emerson likes to go big or go home and she's insisting that she learns to play the Harp!  OMG what is that going to cost lol and who wants to be the one to tell daddy?!  Anyone out there have any option on the Harp or experience with it?!