Based upon a near lifetime of fly fishing (I'm 53 abd started fly fishing at age 5), which included teaching a few hundred folks how to fly fish, I'd recommend an
8'6" - 9' 5 or 6 wt rod. If you are only going to fish for trout, the 5 wt would get the nod, if you are also going to fish for smallmouth and largemouth bass, the 6 wt is a better choice because it cast bass flies better.
You should have no problem getting a good outfit (rod, reel, line, and backing) for $300.00 that will serve your needs for many years. Rod Companies like TFO, ECHO, G. Loomis, St, Croix, Lamiglass, Redington, and Scott all produce good casting rods for under $150.00, and some of them such as G. Loomis, Redington, and St. Croix have good casting, complete (rod, reel, backing, and line) outfits available for about $200.00.
The best thing you could do is go to the closest fly fishing shop (or fly fishing specialty store if you will), tell them what you are going to use it for and how much you can spend, and they will provide you with an outfit that will fit your needs and budget. The local store will also more than likely give you some casting instruction and in general be a very good source of information on casting, knots, flies, etc..
The second best thing you could do is contact one of this sites sponsors, tell them what you are going to use the outfit for, the amount you have to spend, and then they will be able to provide you with a good choice of equipment too. The reason this is the second best choice is unless the sponsor is close to you, you won't have the personalized casting and other help you may need.