The answer is, not much, but if you are serious about playing, an extra $980 is probably worth it. In this video George Elmes compares his super cheap yellow starter uke with his most recent uke purchase, a $1000 beauty. Listen to him play the same song on each uke. The expensive uke has a brighter sound, but the $20 uke sounds pretty good. Elmes says the expensive uke holds a tune better, has better action and intonation, and feels better to play, "however, you can still play a tune on this $20 yellow ukulele."