Hi I am a UK uke player so can't advise on US suppliers, but I would agree with tootler's advice on makes and helpful links.

It is preferable to try instruments out if possible, but of course that may not be possible depending where you live. One thing to consider is the size of the fretboard. I started with a concert sized uke but after trying a friend's tenor I preferred the slightly larger fretboard; it could be easier for a beginner, although hand size may be a factor too.

If your budget will stretch to a model with a solid wood top then that gives better tone (spruce is usually cheapest). And I would recommend Aquila Nylgut strings for lovely mellow tone.

The uke is a smashing instrument and great portable fun.