Around the time I got my first Pi, last april, it was my birthday, so I asked for a particular python book, as its always difficult to buy a present for the guy who has everything
Anyway, I got a quarter of the way throught it, but now whenever I,m trying to do something in particular, I just google it. There's loads of tutorials and help out out there.
And python is so versatile too - with plenty of add on libraries and tools. So if you want to avoid spending any money, you don't need to.
Then again, it is nice to have a book sometimes.............
Various male/female 40- and 26-way GPIO header for sale here ( IDEAL FOR YOUR PiZero ):