... I suspect this will be significantly cheaper than the non-nickel MQ, maybe even under or around $100.
Not a chance, sorry. It may or may not be a bit cheaper, depending on things like whether it's just the parts or a full kit with manual, mounting screws, wire, and possibly the impedance switch PC board. I don't have the latest numbers, but I don't see how it could be less than $200, and it might well be the same as the MQ parts.