What is a better buy on frozen orange juice ml for 1.95 or ml for 1.80?

The question of "better buy" is not the same as "cheaper". One consideration depends on the dilution required to put it on your table, If the dilution for the higher price juice is lower it might be a better value for the price. You must also consider the quality of the brand. Poor quality (or taste) juice is not a bargain.