And of course there is also the harmonica... Comparitavely inexpensive even for good ones. And it really is a real instrument in spite of what some may say. Certainly no less real than a uke...
Hey, Paul. As you know, I do uke, mandolin, fiddle and whistle.Nice thing is, the more you do it, the easier it becomes switching back and forth. Try adding some completely different instruments to the mix, such as pennywhistle (many different pitches), flute (added embouchure issues), fiddle(bowing), concertina (that push-pull thing) etc.
I like to screw my head up with a good single malt.