I would recommend a HUD from PT4 or HM3 but as most of the sites CardsChat has
freerolls on doesn't have HUD usage you could work up to platinum level and wait until you've made the money from poker before you buy it.
So far as educational content there's quite a bit of resources on CC under the poker tab at the top, start from there and work your way through then once you know where you stand and what you need to work on you can use your CardsChat freeroll profits to pay for paid content.
Once you're looking to pay for content, try and find a coach / site you relate to before you pay for coaching, as having a coach or instructor you can understand and is able to speak at your level of understanding of the game is really important. There is no such thing as the best coach or the best coach, it's whatever works best for you that is going to have the highest value.
Hope this helps,
GL
EDS