I've been using Outlook since Outlook 97. Of course it is not free, but IMO, well worth it.
Google mail (Gmail) works (and I have several Gmail accounts) but Google is notorious for false positives (good emails tagged as spam and shoved into the spam folder) forcing users to periodically check our spam folders before any good emails are automatically deleted.
You really need to decide if you need a "local" email client or a web-based, or both. The problem with local clients (running on your computer) like Outlook and Thunderbird is once you pull the email down, it is now on that machine and not available for viewing from another computer.
Web based email clients like Gmail store your emails in "the cloud" so you can access your email from anywhere.
I use MailWasher Pro
as my spam blocker but also as my email organizer. MW lets me view all my emails (I get about 60/day) from all 8 of my current email accounts and puts them in one UI. Then I can delete, reply, or save them from there, pulling down only the "keepers" with Outlook for permanent storage on my machine. If you "work" forums and get dozens of forum notifications each day, I cannot emphasize how easy MW makes "working" through those notifications.