4MB RAM?
And a $10/mo DigitalOcean droplet is enough for me, for you, maybe double that.

Interesting,
Might try to tweak my settings a little and see how it responds.
Hosting own makes sense if one has access to reliable connections.

Take a look at BuyVM. They are reliable and competitive. We have at least 9 servers with them.

The small 4 Cores @ 2.00+ GHz 2GB Memory 150 GB SSD Storage 10 TB @ 1000 Mbps is just $24.95/month and it is very capable. We have 13 domains (46 accounts) in total in one of those and it just goes. (2GB + 2GB swap file ssd).

They also have bigger plans (4GB 4 Cores and 8GB 8 Cores) but you really need to hunt down those plans with them because their stock flies off the shelf.

Indeed Zhang. Linode is great too but more expensive when it comes to features per buck (no that they aren't worth it); they are a terrific provider as well.

I recommend BuyVM specifically to run iRedMail in a tighter budget. We use them because they provide free Anycast network (IPs included), Failover IP, 1000 Mbps Network In/Out, etc. and these little beats sit on SSDs. For example, our Load Splitter Service for Roundcube Webmail runs completely through BuyVM Anycast and we push a good amount of data through it daily for hundreds of users. Our iRedMail boxes with them just go and go... that's partially because iredMail is fantastic though

See, their little 1024MB (2048 Burstable RAM) is also a 4 Core VPS... CPU cores are a must, and it's only $12.95/month sitting on SSDs. Take that and add a 10-user edition of iRedAdmin-Pro (without source code) for FREE.  It is a win/win no brainier solution for users embracing iRedMail on the budget; a smoking fast and cheap one I must add.

The extra savings is better used towards the iRedMail-Pro license. That's how we see it and how we recommend it to our supporters because we believe there is an immense value in both, BuyVM and iRedMail-Pro. Behind are the days when setting up a mail server could be a whole-weekend task! Else, there is always Gmail .

andrzej, I have already recomended DO