This post lists the difference in price between LinkedIn Free, Premium Business, Sales Navigator Professional, Sale Navigator Team and Recruiter Lite. It also lists some of the key feature differences.
The end result is a bit like comparing apples to oranges. However, I put it together to see whether the "Sales" or the "Recruiter" interfaces would work better. For my needs: building a list that I can import into a CRM it appears that purchasing the Sales Navigator Team month-to-month is the most cost effective. I will get 30 InMails and 25 Out-of-Network Unlocks. Each month I need it, I will pay for it.