A bagel shop charges 75 cents per bagel for orders of less than a half-dozen bagels and 60 cents per bagel for orders of a half-dozen or more. For example, if a customer order 2 bagels, the charge is 1.50. If a customer order 7 bagels, the charge is 4.2. Please implement this function, and return the number of the cost.

bagel_cost(0) 'The cost is $0.0' bagel_cost(1) 'The cost is $0.75' bagel_cost(2) 'The cost is $1.5'