I typed a big long reply, but the useless poxy wifi in this place decided it was a great time to disconnect, and lost it as I posted, grrr
So short one.
ISP provide is best "free" one, but tied to ISP, and changing email addresses is a PITA
"Free" like Gmail isn't free, Google look at your mails to build a better profile for their advertising and data selling business. But as most of us use Android anyway, we obviously clearly don't care about our data and privacy, or the privacy of family or friends (clearly, judging by the number of people here on arsebook)
Low cost paid for services may be of interest to some, usually around £5-15 a year, depending on requirements.
I use mail.com, about $15 per annum, and allows me to change ISP easily. I don’t like gmail for the reasons Jaime quoted.