Sam Morgan Moore from Half Inch Rails presents a new shoulder pad solution for handheld rigs.
These rubber shaped elements are not only very affordable at £30 ($48), but as opposed to common shoulder pads they are also really small.

from the HIR website:
HIR_SP Shoulder Pads are super soft plastic pads to create a shouder pad for your 15mm camera support rods
Sold as a set of five or individually
The pads make for a cofortable shoulder mount while being super compact and low profile, especially when your rig is packed down. The pads are egonomically curved to fit your shoulder while maintaining a level horizon with your camera. The web design means they compress to your exact shape on the shoulder.

Get it for £30 ($48) over at Half Inch Rails