I ordered them at my LBS. Saris makes three models.
There's the
Bike Trac (in the Work pic), which is the cheapest ($40) and is carried at QBP, so any LBS can order it.
The
Locking Bike Trac (in the Home pic) has a loop to U-lock the bike to the rack. At $80, it's a commercial product and must be ordered form Saris directly. Not all LBSs have a direct account with Saris. Trek and Specialized dealers can order through their dealer distribution.
In between is the
Cable Locking Bike Trac. I don't own one so I don't know the pricing. It's also a commercial product.
I like the Bike Tracs indoors because, A) they look nice, and B) the trac keeps wet wheels off the wall. In the garage, a $5 hook from the hardware store will work just as well.