Even at $100 the mojack is a bit pricey unless you have a larger mower or a service shop. For my 30" and 34" rear engine riders, I find a bumper jack that came with an '84 Dodge van works just fine. You can likely still find these in junk yards.
I own a John Deere Model 68 rear engine riding mower. I think it's at least 30 years old and parts aren't available anymore, unless they're also on later models or later parts can be substituted. This has 2 blades with a total 34" cut, ideal for a 1/2 acre lot. Mowers this size are rare these...