I suggest a french link snaffle. No buckling action and extremely mild. I wouldn't suggest buying a very inexpensive bit - you get what you pay for. A decently priced bit shouldn't have any rough edges or blemeshes like a very inexpensive one may and will last a little while if liked. Expect the horses to be pretty non-responsive when transitioning, they will be looking for the harshness of the gag. Over a couple of leasons, the horse's mouth softens, they accept and it is a much better picture, in my opinion.