You can get MonsterFlys for $50 on Eastbay:
https://www.eastbay.com/product/model:57262/sku:09278061/Nike Monster Fly – Men’s?supercat=home&cm=GLOBAL SEARCH: KEYWORD SEARCH#sku=09278061
I’d suspect they actually could be somewhat beneficial for slower (23+ and 51+) 200 and 400m runners with less than ideal foot strike.