Sideloading on iOS is as easy as installing the free Cydia Compactor on your PC or laptop and dropping an app on it.

The downside is that self-signed certificates only last seven days unless you have a paid developer account, but if you're comfortable with jailbreaking (which is even easier than sideloading since you can do it just by tapping a link in Safari on iOS) then you can install Reprovision which automatically renews certificates for you every few days.