One inexpensive source of bananas is swap meets. I have seen pups sell for about $3.00, & 6 specimens for about $10.00. The varieties might be unnamed, but sometimes they are unusual, and sellers will often present their fruit alongside the plant. Another source is Asian markets. They are more expensive, but I recently saw 6 edible varieties in pots for about $25.00. The cheapest bananas I have found are at the dollar stores  unnamed varieties for, of course, $1.00.
Having said all this, if you want named varieties, others will probably suggest nurseries. They also sell them at your local department and home improvement centers , but you need to check out the varieties to see if they are edible.

You can look for your zone yourself, see link.
Simon.
Search for a banana with a lower rate than your area.

Here is a link that might be useful: usda zonemap CA

Here is another that uses your 5 digit zip code.

Here is a link that might be useful: Zone by zip code

Hi,

On using "usda zonemap CA" then I find my zone as 10a and according to "Zone by zip code" (my zip code - 94555) then it says "The maximum plant hardiness zone for your zip code is 9."
What should I consider (10a or 9)?

Hi Baci, Thanks a lot for your suggestion. Let me search for the local swap meet and Asian Markets. I usually get my stuff from the local nursery 'Regan Nursery'. I would check with them too.

To be sure, take a low number. ->9b
In a south facing garden with hedges, you could try 10a plants. USDA is only an indication, not reality. You could also have a cold winter.
Simon

Joe is right on the money.
Many varieties of bananas just don't do well close to the bay. They may put on nice growth, but if and when they do flower, the fruit doesn't develop right and it rots.
This even happened to me here in Modesto with Goldfinger.

Anyway... if anybody is interested, I have some nice fat California Gold rhizomes that i'll let go at a very reasonable " midwinter " price.
Drop me a line at... tropic2tropical(at)hotmail.com if interested.

Jeff

That "zones by zip" is incredibly conservative. It lists my small zip code as 10 and 8. Zone 8 is 10-20F. Even the coldest microclimate hasn't seen

I would be interested in the varieties California Gold and Texas Star. Thanks, Mick