Many sites such as Jigsaw, Lead 411, and others charge a monthly fee. Also, LI InMail can be expensive.
My first choice to find an email is Linkedin.
My second choice is to google their name and email... i.e.: "Vince Fowler - email"
It doesn't take me very long to find what I'm looking for. No more than a couple minutes at most.
If you're looking for a *list* of names and email addresses, my strategy will be slow and painful. If that's what you're looking to do... it smells like spam to me, just saying.
If you're looking to target specific people at specific companies, my strategy works extremely well.
As for LinkedIn's cost for InMail... you say "expensive", I say "investment"
To me, Linkedin is a minimal investment. My sales more than justify the price of my LinkedIn Premium account.