Careful there--it's an addiction...
Y'know, I almost bought a boat once, but it needed a motor, and a steering systen, and a trailer, and a paint job...a $1500 boat can cost $5,000 to put in the water.
Likewise, a $100 fly rod can take $1,000 to put on the water. Besides the cost of a reel (and extra spool?) is the cost of a line (or lines?) and the cost of several sink tips and the cost of flies and boxes to put the flies in and books about the flies and fly fishing and an extra vest with pockets for the fly boxes and a tying vice because buying flies in the store isn't cost efective and then there's all the materials, of course, and then not enough boxes for all the patterns you've tied or caught fish on or want to try to catch fish on.
But then, I don't mean to disuade you--fighting a steelie 1:1 with a fly reel does things to a guy.
Still, a word of warning: read up a bit. Look at
http://www.flyfishsteelhead.com/. The articles there are "fantabulistic" for starter-fly-guys.
Course, what do I know? I fish 5, 8, and spey--and cast the 8wt further than I do the spey rod.
Oh well. I use and would recommend a Tioga reel. Like Dennis say, fly lines hook fish; fly reels land them.
Can't say I'm a purist, though. Today I caught my first winter-run of the season. On eggs.
sharp hooks--