I found these at Target last fall when they were heavily discounting all the Stok grill items. I picked up the grates, the lifter and a bunch of the inserts for as much as 60% off. I'll be completely honest and tell you that most of this stuff is of "questionable" quality. The $20 I paid for the grates was cheap enough to justify the time it took to season them properly......I think.
The gap between the grates is wider than I would like and the grates themselves are beveled and not really cast in a consistent way. The grill marks these produce look ok but require a grill press to give a nice presentation.
They did season well, heat quicker than I expected and are now completely non-stick.
My favorite wok fits nicely into the insert opening and I get the proper stir-fry temps with easy when using fuel baskets.
They work well enough that I use them all the time now and the lighter weight seems to be a benefit when it comes time to remove for cleaning or to add fuel. I don't know what the retail price of the grates are but they were certainly worth the $20 I paid.
I will add that my wife had to inspect several grates to find one of good quality. Some were cast so poorly that the insert did not seat properly. Consider that as well.