When it arrives, if he says anything, I might say "Boy, I learned a lesson. This wasn't such a good deal after all. By the time the shipping costs and stuff were added in, I wound up paying a lot more than I thought -- even though it was still less than I've seen it on sale locally. I'll be more careful next time I bid on something on eBay."
And, if any of your quilting friends wants to know, I'd also say something like that.
Otherwise, I'd leave it alone and not bring it up again "voluntarily". Do some "penance" by making a couple of nice charity quilts using the new machine......
Of course, men never lie about anything and they always voluntarily offer apologies if they DO slip a bid and bend the truth, right?