Say you're in the market for a pair of jeans. You could get a pair from H&M for $30. They're cheap. But what you really want is a pair of Levi's. So you wait for the Levi's to go on sale. Both jeans are cheap, but one offers better value.
But if "super" cheapness is determined for H&M jeans, even though the Levi's are discounted, they may be equal bets. I just stick to what I think is painfully obvious. No mediocre ideas.