Some vendors price their bananas by weight, some "by the banana". This can make price comparison confusing.
Trader Joe's: $0.19 per banana (non organic). Their bananas are typically smaller than you might find in a supermarket which would sell them by weight.
Target: $0.xx per banana (non organic).
For the by-the-banana shops, we probably should get a statistical analysis of banana weight, so that we can better compare banana/dollar values.
The USDA grades banana size/mass as follows: extra small (less than 6" long) : 81 g small (6" to 6-7/8" long): 101g medium (7" to 7-7/8" long): 118g large (8" to 8-7/8" long): 136g extra large (9" or longer): 152g
Some bananas can be grown in your garden in Davis, with varying degrees of frost protection needed. After the second year, some types might flower and set fruit, which then takes a number of months to ripen. Bananas can also be grown as houseplants but will rarely have enough light to flower.