This is my first post, so please tell me if this is off topic!
I have had my own mail server for over 20 years, and have switched ISP's because of port 25 blocking. Unfortunately, all the ISP's in my area are blocking port 25 because of spammers setting up their own private mail servers on their network. So, last summer when my ISP (the last of the ISP's port 25 blocking), I had to make a change to an external host for my email, but I did not want to pay for an email server (most are crazy expensive).
I ended up searching for a free solution that would give me about 5-10 email address' for my domain. I finally found a company called Zoho (it's an Indian company) and they have a free service that gives you 10 emails with a 2GB per email account. I've been using them for about six months now and it's a great alternative, if you have no other options!