Host the server itself on something like Raspberry PI (~ $30 at home, and in case of a breakdown — have the same in reserve.
p.s. The disadvantage of such a solution is that you need to be a bit of a geek and you need to understand that if something breaks, only you can fix it yourself.
p.p.s. You can also look at commercial solutions like "Siemens Logo!", then replacing a failed device will be easier (albeit more expensive).