Last time I went to Morzine would have been about 4 or 5 years ago and we got a cheap apartment just by googling, found a brit landlord who was astonished that anyone wanted to rent his place in the summer. I'm sure things have moved on since then, but even in Chamonix last summer there were loads of empty apartments, and that's in a town even more set up for summer holidays than Morzine.