Things will be rated in stars: * is 1 star, etc. * * * * * is 5 star.

JAVA
bedrock


1. Minehut. * * * * *
Minehut is probably the best free server hoster out there. I've seen people complain that they can't join without an online owner though. This can be managed by joining the Minehut lobby (minehut.com) then doing /join [​server name]. The server will start up in around half a minute.
Sidenotes: People who live in the Oceania area will experience high ping due to the fact that minehut's data centre(s) is based in America. 10 players can join in one server, so this is good for a small group of friends.
Link

2. Idleyhost * * *
Idleyhost is a good hoster, but many things bring it down due to its disappointing performance. The data centres are situated in Germany, giving you considerable ping, however you will have to keep on trying to host over and over again due to the limited amount of spots, etc host in Free 1, Free 2, Free 3. If you keep the server tab open, the server can run 24/7. However, the downtime is significant, as it can range from 30 minutes to 70 percent of the day's downtime. However this is a relatively new server hoster so hopefully it'll get better. This hoster is best for running a 24/7 server, but it has low performance.
Link

3. Aternos * * * *
Ah, Aternos, the saviour of Bedrock. You can host both Java AND Bedrock. The server's RAM increases the more people are playing. It's hosted in America, which is good for most people. And it offers more customization than any of these ones. However, it cannot run 24/7. You have to wait in a queue, and when the queue is over, people have to start joining or else the server will go offline again in about 3 minutes. Otherwise, this is a good and reliable server hoster.


I hope this has given you enough information for you to start your own server. If not, then maybe you could pay for them instead. Excellent paid server hosters include:

Apex hosting

Scalacube

Shockbyte (people often complain about its customer service though)


There you have it! A nice list of servers. I hope the start rating helped as well. If you can, give a diamond and maybe a heart as it helps me out a lot :)