Members might recall me demoing how to use PGP to send/receive encrypted email with an existing email client. It does involve a bit of work though in getting things working. That's the downside. The upside is that you can use with any email service since PGP is just a layer on top of email.
But there's an easier way and that's using an encrypted email service like ProtonMail which handles all the encryption/decryption within the online client (or app). The downside is that you only get the benefit of encrypted email if you correspond with other ProtonMail users. Thankfully, there is a limited free option so everyone can get one and you could use it just for particularly sensitive emails.
Their free accounts have 500 MB storage and limited to 150 messages per day and limited support. 500 MB might not sound like much but that's a lot of emails. I've had a Gmail account for 12 years and am slightly over 2 GB. I also pretty much keep everything which includes emails with attachments.
The lowest priced paid account is Plus at $4/month and includes 5 GB storage and up to 1000 messages per day. The Security Humble Bundle I purchased recently gave me a $25 credit which I am using towards the Plus service. It's also how I know about ProtonMail. I have no idea if it's the best encrypted email service out there but the bundle only cost $20 CAD total and also gave me a year of 2 TB of SpiderOak One encrypted storage so I already feel like I'm ahead of the game.
The Plus package allows for 5 GB of storage and 1000 messages per day plus other extras like the ability to send encrypted email to recipients outside of ProtonMail (using 1-way encryption). labels and filters, and your own email domain and priority support.
You can
sign up for a free account and find out about all their packages or just find out more about
ProtonMail generally. Oh yeah, it's also Open Source-based and its servers are based in Switzerland which has strict privacy laws.
If anybody tries out the free service, shoot me a message through the forums with your email address and I'll send you one back.