We've given a number of ukulele's as gifts this year...most of them inexpensive painted 
Mahalo's.  The 
Mahalo ukuleles come with pretty lousy strings (something we realized too late before gift-giving came).  Even after you've tuned them numerous times and they start to stay in tune, they still sound pretty bad.  We tried putting on a number of strings (we ended up getting green and purple 
Mahalo ukuleles for ourselves...it's a 
uke thing).  We found that we really like the way the 
Worth Brown Fluoro-carbon medium (BM) strings sound on the 
Mahalo ukuleles.  The strings are somewhat pricey, but they give you enough length to do two 
ukuleles with one package. 
So for what it is worth, we recommend the Worth Brown 
Fluoro-carbon medium (BM) soprano strings for the 
cheapie-er-moderately priced 
Mahalo ukuleles.  You can 
purchase them at 
Elderly Instruments (a cool shop with a decent 
ukulele selection).
Yes, these are basically fishing lines.
