How much work do you want to put into it? Do you like building things, like to constantly tweak settings to get things totally perfect, like working with Photoshop type software, done any programming, are you a patient person? There is a learning curve and it can be frustrating at first, but it can also be fun and challenging. The product isn't as mature as it could be, as it has limitations and quirks that should be fixed or improved. The good thing is that they are working to improve the product, and the community forum on the iRule website can be a great help.
Do you have a networked receiver? If so, you could try the trial version and see if you can get some buttons to work with the networked receiver, without having to spend any money on hardware at first. To use other devices, you will need to purchase a iTach unit for about $100. As I said, it can be frustrating at first, but once you have a few buttons and a couple pages working, it isn't that hard. The help videos aren't much help, but the tutorials cover just about everything, though the tutorials would be better if they had more thorough instruction for a beginner. When you forget the proper sequence to doing something, the tutorials will be a constant reference. Like I said above, the commmunity forum on the iRule website can usually answer specific questions that come up.
I've been learning iRule myself the last few weeks, and have asked a lot of questions, but I think I pretty much have it down now.