Weren’t these $50 msrp?
I can’t find an MSRP for this particular model but the price is less than Amazon’s (right now it’s $105.06), so I’m inclined to think it isn’t that low. There are other models, so you might have looked at a different one.
Screen Capture pulled from an article written by PC Mag back in the day. Its a bluetooth device, so shouldn’t the newer version work retro back to older devices? I know I use SP3 and SP4 at work, and use the pens from both interchangeably between the two different surfaces. here is the image and link: