I'd like to give you a few more details from my personal experience. I started playing when the game when Free-to-play less then a month ago and I'm currently level 34 with a couple low 20's alts.
My first suggestion, is just go ahead and play the game but keep in mind that after about level 20 if you decide not to pay you're going to be VERY limited on what you can do in the game.
If you are enjoying the game you can go to a site like Amazon and purchase the Mines of Moria expansion for ~$10 (US) this will unlock not only the 50-60 content/level cap but also give you access to the other two classes, two permanent character slots, permanent "premium" (not to be confused with VIP) status, and 1 full month of paid subscription (which includes 500 turbine points ~$5 value). If you load the expansion around level 20 you should easily be able to get to level 40...and this is for $10, if you still love the game and decide to either subscribe or purchase points at this point at least you'll KNOW you enjoy the game with very little invested.
You can also go ala carte, but at least for the lower levels this gets very expensive because you need the quest pack(s), you'll want extra bag slots, riding skill, and swift travel. Although most of these things are permanent and you'll never pay again they do get costly. So it's usually a better deal to just subscribe for a couple months, get a couple characters to level 50, and then use the turbine points you've saved to buy the absolutely necessary stuff.
Overall it's an EXCELLENT game, and I've played nearly every commercial released MMO since The Realm over 13 years ago. It's worth playing, just don't expect to play forever for free. However, if you're WILLING to spend money if you like it, leveling to 20 gives you a very solid grasp on whether it's worth paying for.