Roasted coffee beans can cost more than $50/kg bag. I decided to roll my own and buy green beans and roast them. Green beans start at around $10/Kg, and you can mix/match/roast according to your taste desired.

Ive just done my first successful roast. But note if you follow info on Youtube you can come unstuck.
Youtube roasts invariably are done outside in the open to avoid smells and my first roasted beans were outside the house in the popcorn maker roasting for half an hour with no success.
I figured that New Zealand less temperate climate than elsewhere may heatsink the popcorn maker, reducing its heating ability, so did another roast in the garage in a box as below:

Note the paper towels, which helped raise the chamber temperature. When I removed them for the third roast it was not anywhere near as quick, so assume the towels restrict airflow and help the roast method.
The box is needed to collect the copious chaff that roasting beans generate, and help contain the airflow more; effectively reheating the same air.

Dont roast inside the house as your wife will get a tad annoyed with the smell.

Note you must get a popcorn maker with side vents and at least 1200w. If unsure you can PM me.

I used a fire alarm near the garage as an indicator of the roast ready. When the alarm fired, the roast was of the desired colour and 'First Crack' was over. I have not heard the 'Second Crack', but the beans were darker than my commercial beans anyway.
They should be smoking when you pour them out of the Popcorn Maker into a stainless bowl or similar.

Will report on the quality of brew in a few days, as the beans need 3 days to mature after roasting.

Kind regards,
Alistair