Maybe I'm a little behind with my MacBook Pro but I just learned that you can download apps onto it just like you can on your phone. Now that I type that I'm certain I'm behind.
That's not exactly by big tip though...I'll give you the short version. I needed a program on my Mac that would allow me to merge pdf files that didn't cost $400 like the ones at Adobe do. So I downloaded pdf Suite- for $1.99- yes, one dollar and ninety-nine cents! And it does exactly what I needed- to merge pdf documents. Finding this made my day!
Then I needed something that would allow me to add and remove security settings from pdf documents, so I downloaded Secure PDF for a mere 0.99 cents. Money well spent if you ask me!