Let you in on a little secret I work in Electrical Wholesale and for us to break even we have to make 21% on cost... That's before we even start making a profit. So buying something for $10 and selling it for $11 isn't actually making money. It's not as straight forward as it all seems.
My parents had a retail business and it was pretty similar for them - across the year, the cost of running the business (staff wages, overheads etc) was 25.5% on cost price or 125.5% total, though this would have been much higher had certain "high ticket" items been removed from the equation. I don't know what the "mark up" is on sporting goods, but their list price tended to be between 190% and 230% of cost price.
iIf those numbers transferred accross, which I'm not saying they would because the latter figure came from some very lucrative import lines specific to their business, then you'd be talking about 130% and 161% cost respectively. So on the lower end, you'd be talking pennies in profit...
Of course, there is the argument that this sort of thing generates custom that might not otherwise have existed (I, for example, would be unlikely to consider top of the range M&H bats!) and I can guess at other benefits it may bring, but it remains an offer that is generous to the point of insanity!