Go wuth what you have. Old laptop? Works! Old desktop? Also works! Old android phone? Might work! (VM/terminal)
If you have a device that can run Linux, start with that. Once you get some usage you can understand if you need an upgrade, and what kind. Maybe you will findout that this old laptop that you had works perfectly and you can sace money on buying a server.
Lucky you! I've got a simple solution, only use single use plastic, then all you have to do is just put a big plastic bag over your table and when you're done eating you just pick up the bag, close it all up and throw it away and that way you just leave the problem to your grandchildren and they'll die from climate change.
Not much, just don't build it over theft.