Any home improvement store (Home Depot, Lowes, Menards, Fleet Farm, Ace, True Value, etc..) will have these. They may be called "filing cabinet/drawer locks". They are typically found in 7/8" and 1 1/8" lengths. I believe the Bally Midway coin doors use 7/8" ones (but you can always bend the bar the 1/4" forwards or backwards as needed if you get the wrong ones).
They should not cost any more than $2.99 each.
Bob Roberts has a pack of 2 7/8's and 1 1 1/8" for $7, but add $6 flat shipping if you dont want anything else, and it costs more than buying locally, though you get them all keyed alike from him.