Well...depending on the availability and demand of the MCI cards, I can't say if that's a good deal for all three cards...but if it was my machine, I would buy them at that price.
They are invaluable for working on the deck, and with some machines, or some situations, they may be an absolute necessity just for being able to adjust something that is impossible to get at without the card. Not sure if that applies to you MCI model.
With the single card that is needed for my Otari MX-80...the second one that I bought last year, I paid $80...it was brand new, leftover in someone's stockpile.
I saw a third one also last year, where the guy was asking $120, but was also taking offers...but since I didn't go for it, I don't remember what it ended up selling for.
The first card I have came with the deck.