Unit rate is total price divided by quantity. This gives you the cost for 1 item.
Unit costs:
2.99 / 6 = 0.4983 each
4.49 / 9 = 0.4988 each
5.99 / 12 = 0.4991 each
3.49 / 8 = 0.4362 each
The Best Buy would be the one with the lowest unit price.
The Best Buy would be 3.49 for 8 candles.
