Looking for advice on learning GP-Pari

[Daniel]

Several years ago Stephen Wolfram offered to give me a copy of Mathematica. Unfortunately the gift was only for one year. A few times I reached out to Wolfram Research to renew Mathematica. Wolfram asked me to write Mathematica software for Wolfram Functions supporting tetration, but I have to either buy or beg for Mathematica. So time to move on to a public domain mathematical programming language. 

What resources do folks recommend for learning GP-Pari? I looked on Amazon and there is only a couple of expensive books on using the programming language. Is it all just online resources? 
Thanks,
Daniel

So lucky for me I come from a strong C programming background; therein Pari-gp was only a slight difference in syntax.
...
Honestly, I've found Pari-gp to be one of the most natural languages. But that's also because for me programming in Java or Python is a nightmare, where as C is fucking awesome. Honestly, the beauty of pari is the online resources. Use them. They're fantastic!

I'm not the best at Pari, but I know how to use it for what I want. If you ever get stuck just pm me and I'm happy to help

Regards, James

Thanks for your kind offer of help James. Fortunately I'm comfortable with C. 
Cheers,
Daniel