Cheapest one I saw was about $9000.00 at a food show. It cooks useing a combonation forced circulating ( what they call impalled) hot air and microwave.
I have never used one but have been told by people I know that have, that they are pretty good, but had to require service twice in first 6 monthes they had it. This could be said for a regular oven also as far as breakdowns.