yea, if all you are doing is freerolls, I would defo wait. If you KNOW you are getting one and you KNOW which, then it doesent matter, but a HUD will just be a novelty if all you are is a freeroll player. So the trial will be wasted.
IMO a HUD is also only going to help you if you have an idea what to do with the stats, as well as have a good grip on your current game, a HUD will not turn a losing player into a winning one.
I look at it like any tool of any trade. Take a cook as an example. If you have no idea how to use the spices, all the best pots and pans, and the newest stove tops in the world will not save your bland sauces.
I thought a while before getting one, and to be honest, I had it a while before it was any kind of help, since I did not really know how to incorporate the info I got into my decision process.
Now, I cant imagine NOT having it, which is also a double edged sword. But as long as the sites allow them, I will use them. I also multitable and cannot imagine how to do that w/o it as well.
Many good players (mainly tourney players however) claim to not need one, so playing a good game is simply step one before anything else.