We've been fielding some inquiries on why the sets are expensive and why we went with the base+child pricing structure over on reddit. I felt, for the sake of transparency, to post our statement here as well:
"...To be honest, I was initially apprehensive to push this sale simply because I knew there would be some sticker shock. We've had many people suggest that we charge significantly more because they knew running a sale like this isn't a worthwhile endeavor.
A sculpted 1u keycap, at its lowest, generally sells for $15. When making a full modifier set, you need to reinforce the base/stems and are dealing with multiple sizes and profiles. At the end, we felt that $6 per key would allow for the investment in time/materials/labor to be justifiable.
I understand that it may seem a disadvantage to HAVE to purchase a base HHKB set. I'd like to remind everyone that the ONLY extra key you would have would be the short shift key. The Realforce set consists of an extra 2x 1.5u modifiers, long shift key and Backspace. Keep in mind that one of the 1.5u modifiers requires a "rotated" stem and requires a considerable amount of effort/time as well as a dedicated mold just for RF. All in all, with the $20 price point for the child set ($24 full price), you are actually paying less and having the option of switching to a HHKB as well.
As for the Leopold 660C, new molds need to be created just for the 1.25u modifiers. Of which, a 660C requires 6 to complete the bottom row. This also includes another duplicate shift and backspace. At $32 for this child set, we are taking a hit to provide support for 660C users.
At the end, we would've ended up charging more if these were stand-alone sets (for RF and 660C). For a more streamlined production process, we felt that the bonus of having multiple support and discounted prices for child sets would be worthwhile to most."