Not sure what you mean with "puck-style" detergent, but here in the UK, I always tend to buy 100 dishwasher tablets for £12, which works out to £0.12 per wash,

Not sure what you mean with "puck-style" detergent, but here in the UK, I always tend to buy 100 dishwasher tablets for £12, which works out to £0.12 per wash, and Rinse Aid for £3.50, for which the company claims 80 washes (though I haven't measured), which works out to £0.044 per wash, for a total of £0.164 per wash. £43 for 90 washes is pretty outrageous.