cm - centimetres- because of the size, however some might measure in inches which would be less accurate.
It depends upon your motivation. A raffle ticket can be a donation to a good cause -- not sin. Or it can be from a desire to get a lot from little, or greed. Greed is sin.
I would measure it with a ruler.
centimeter
Any measure of length will do, but the most common would be feet or meters.
You would answer it with cubic feet
length
If you don't return the money, most definitely. And there are likely to be penalties for running an illegal raffle.
A metres, for an approximate measure, a centimetre for a more accurate measure.
You would use meters.
I would use feet
cm
Inches