Now here's a thing - I agree with spaced - by far the most economical way to do this and the way I went about it for years, however the kids left home and we downsized the house and now I buy ice from the supermarket 'cos....
.....Now the freezer is in the garage and the tap is still in the kitchen. That simple algorithm contributed by spaced - fill tray, put tray in freezer - equates to fill tray, carry to back door, realise that it's locked, put down tray, get keys from keyboard, unlock and open door, pick up tray, head to garage, find garage door locked, walk back to utility for garage keys, return to garage, unlock and open door, place tray in freezer, reverse path to house locking up as we go. Give tray enough time to freeze. This usually means going out once too soon when only the outside of each cell has frozen and you can still see movement and bubbles and then a second time when not only have the cubes frozen but the tray has become welded like Shackleton's Endurance to the bottom of the freezer compartment. Finally empty ridiculously small number of blocks of ice into bag and then go back to step 1. Building up a sizeable stock of ice cubes this way is a pain in the proverbial, so Tesco and Polarcube get my business on a regular basis..