Does worst mean:

• least able to achieve their stated agenda, ie worst at their job. (Trump)
• worst vision for America, ie most evil (Reagan)
• worst overall impact to America, ie one you’d kill with a time machine (Bush Jr, but Trump might catch up in term 2)
• Worst for the world, ie the one I’d kill with a time machine (Washington)

Although I’m not American and don’t know your history that well.

Facebook market place unfortunately. Or just walking around on garbage day.

Here’s a case + 500w psu I picked up the other day:

(if you already have a case, hdds, psu, and cooling on hand.)

You can also get all of those except the hdds for quite literally 0 dollars, although depending on electricity prices and what upgrading you want to do it might be better long term to spend on the psu.