The guys at Blue Ribbon Flies in West Yellowstone know a thing or two about fly tying and fishing.
Here's what they say about Trout Hunters Fluorocarbon:
"This is the best Fluorocarbon tippet in the fly fishing world today. It's strength is unparalleled, it knots easily, it is extremely abrasion resistant and the handy 55yd spools will save anglers an average of 8 cents a yard over other major brands. At first we balked at the in between sizes, but after using it we've become converts."
They sell it for $24.95 a spool.
Pricey? Yep. But not so much compared to a $1000 rod, an $800 reel, $100 fly line, $800 waders, $200 wading boots, and a cold can of Iron City beer.