SDF.org (the Super Dimension Fortress) offers free UNIX shell accounts. For an addition, very modest, one-time fee, you get an ARPA-level membership with pretty extraordinary benefits. For additional modest annual fees, you get a MetaARPA level membership whose benefits are frankly amazing
This is also the single most useful tool of my IT career. There is no other tool that has been as consistently useful.
I urge you to get a free account today.