I kinda started out like you, but I even had very little spin casting experience. I've backpacked for some time, and here in Colorado I was constantly passing and camping around hi mountain lakes and streams filled with trout that I could see with my own eyes. Three years ago when I really started pounding the trails seriously, I naturally just picked up fly fishing on my own. I'm no expert on the subject, but fly fishing takes some effort to learn and then even more to do well. This was my plan of attack during one off season:

First, find serious fly fishers in your social network and start hitting them up for all the advice you can steal from them. Coworkers, friends, relatives (even those you historically didn't like), customers, etc......as soon as you show interest in their favorite hobby they will talk your ear off about the subject.

Secondly, you gotta either read up on fly fishing or watch some videos. I am a subscriber to netflix, and they have tons of videos you can rent and watch at home. Bottom line, you have to learn the basics of fly fishing (tying knots and casting) before you can ever get on the water to start practicing. These videos will show you how to get started.

Thirdly, you're gonna need a rig setup. You don't know what an expensive rod and reel are supposed to feel like, so start off fairly inexpensive. I first bought a rod/reel/fly line combo from Temple Fork Outfitters for $199. The rod and reel were not very high quality, but it was of decent quality and even came with a carrying tube. And the combo rigs come with everything you need to get started right out of the box. The reel comes with a flyline and leader already spooled on, so just tie a fly onto the leader and you're ready to catch fish.

Fourth, I practiced tying knots at home and practiced fly casting all winter in the park. Come spring, I tagged along with some other experienced fisherman on some day trips and they showed me how to catch fish.......like setting the hook and landing/playing trout.

When it comes to prices on fly fishing gear, the sky's the limit. But most fly fishing rods are made of very light material, and the rest of the tackle for that matter. In fly fishing, weight is rarely an issue (unless you're a die hard ounce nazi), and extra spending doesn't necessarily mean huge savings in ounces. High costs in rods and reels usually equates to action and performance. Even my first cheaper rod was very lightweight. And most rods break down to either 2 pieces or 4 pieces which make them perfect for backpacking. And don't think you're gonna need all of the typical gear when you backpack....like vests, waders, nets, tons of tools, etc. When I backpack or even fish waters close to my car, the only other tackle I take can fit on a lanyard I hang around my neck and the rest can fit into a small camera carrying case.

As for me, I prefer fishing high mountain lakes to cast to trout that rarely, if ever see humans. Just because you fly fish doesn't mean you have to fish moving water. Streams and rivers are fun to fish, but I guess what I'm saying is....lakes can be just as fun.