As many have posted, Gmail is free and ad free. If you use it and you see ads you must have malware installed.
Nearly every time I help someone with a problematic browser, they have malware installed that adds a toolbar to the top of their browser that is the culprit. Toolbars at the top of browser are just a method of getting between you and your Internet access so it can record what you do and they usually get installed without the user being aware that they did it (often as part of some other installation with fine print no one reads).
If there is anything at the top of your browser other than the address bar and bookmarks bar, you don't need it and it should be removed.
And AdBlock can be used (on Chrome at least) as a browser extension to block ads on websites you access although a lot of sites are now blocking your access unless you turn your adblocker off. If the site is worth subscribing to, I will do that or simply not use the site anymore.