Fixing the Front Wheel Hub...

I've been looking for a car to get me around for school and found another cheap 72 Dart 4-door. Looks like it's been taken care of and would do well as a get to school and back and to the occasional cars n coffee meet. (My other Dart I unfortunately have to rebuild the bottom end and I don't have time or money to ship it for school right now.) Thing is, the guy says the outer race spun on the driver's side front and "all it needs is a new hub". The fronts are the typical 9" drums. How difficult is it to replace a hub and drum? I'm not looking to do upgrades, this is as budget friendly to get it road worthy as it gets. Also might be looking for that assembly too for the right price if it's doable. Thank you!