As far as I know, the Rune-keeper class needs to be purchased from the LOTRO store (similar to the Beorning race) but all the other classes are free to play. My character is a Minstrel which focuses mainly on ranged attacks using a musical instrument and healing, though it can do pretty good damage when fighting solo. What do you usually look for when choosing a class? Ranged damage, melee damage, healing skills, or something else?
Here's a helpful page on the wiki in case you haven't checked it out already: [https://lotro-wiki.com/index.php/Class]