If your talking about Tournament play (tho pads can be used in Recball too)..then...it's less about feeling pain, and more about getting bouncers!
Tournament pants sometimes have padding built into the knww and arse areas.
You can get Knee pads and arm pads (protect your elbows and forearms, when sliding but can also make balls bounce off of your arms)
I think there is a body chest plate thing, but I couldnt tell you were to get one, as nobody in Tourny ball uses them.
Elbow and arm pads vary in price, but Planet Eclipse do good ones, so do DYE and you should be able to get either for under $60.