I would search online on Craigslist. Let me clarify that. I would use "Search Tempest" . It is a Craigslist helper and works quite well. I have had great success finding riding mowers on there in Texas. Here's what I would do. Click on search tempest, put in the Joshua, tx zip code, click the boxes that say "has picture", and "search titles only", under keywords just put put riding mower. Then hit search now. You will find quite a few probably in your area.

Here is a link that might be useful: Search Tempset

You can also use machine finder.com (I think that's it).
I found a lightly used , '08(45 hr) JD X300 for $2300 just 2 hours away. I couldn't be happier.

Don't know what price range, but for new machines in the $1500 range I would look at the John Deeres, Husqvarnas (and Husqvarna-made Craftsman), and Ariens.

As for used, check with area John Deere dealers - for example, the one in Weatherford usually has a number of used machines, and others probably have some, too.

And by the way, Joshua is 15 miles south of Fort Worth, which puts it two counties away from Dallas.