Hello Anna,
A barbell pad does help in my case for some exercises, like MIS and BodyMax and I think I would use it for PS too (although I haven't started this rotation yet). I don't use it for PH though (I have noticed that Cathe doesn't so I copied her) because it is a little too big and bulky. If you buy one, try to buy a slim one. I used to use a towel, but it kept falling off.
Have you checked out Argos and Index barbells and dumbells? I have the Argos collection as the plates are smaller (although still as heavy) - perfect for me.
Yen