I don't think low budget vps providers typically allow this. That said, fail2ban works OK, as does manual iptables (now nftables) - unfortunately /etc/hosts_allow is deprecated[1].
If you don't know that you'll be able to arrive from an IP or subnet - another option would be port knocking. (eg: knockd). Although, I'd try to avoid adding more code and logic to the mix - that goes for both fail2ban and knockd.
[1] ed: Note, the rationale for this is sound: the firewall (pf or nftables) is very good at filtering on IP - so better avoid introducing another layer of software that does the same thing.
If you don't know that you'll be able to arrive from an IP or subnet - another option would be port knocking. (eg: knockd). Although, I'd try to avoid adding more code and logic to the mix - that goes for both fail2ban and knockd.
[1] ed: Note, the rationale for this is sound: the firewall (pf or nftables) is very good at filtering on IP - so better avoid introducing another layer of software that does the same thing.