Do you have a signed contract? What does it say about contract cancellation? The chances are good that it contains some at will language meaning that they can cancel without penalty. However, if it does not have such language, they will owe you the full balance of contract. That amount is between 20 and 30 thousand dollars. That is enough money to be worth running your contract by an employment lawyer. You can find one on nela dot org, their specialty association.
Do you have anything in writing about reimbursing your trip to Sacramento for a license?
Here is what you need to do now. Apply for unemployment immediately. There is usually a one or two week blackout for benefits to start, and the clock only starts ticking when you apply. Those benefits will help tremendously when they start coming in. You do not have to be in your home state to apply, and the checks can be sent anywhere.
There will be a bit of fuss that you voluntarily quit your job, but with a valid employment contract in hand that you did not cancel, you will end up eligible for benefits.
Are you in California now? If so, start talking to per diem companies about a job now. Don't limit your search to your immediate location. Have you signed up for several travel companies as you should have? Call them all now about ASAP assignments in California. Can you do other specialties if you must? Perhaps medsurg? Do it! Try a non nursing job with someone like Manpower - eating is important.
Don't be too proud not to look at local agencies that might provide food and shelter. Try also Travelers Aid International at travelersaid dot org. They been helping distressed travelers for 150 years. Another aid society to try is Nurse's House, a national fund for nurses in need at nurseshouse dot org.
Any relatives or friends that can give a short term loan?
That's all the immediate advice. It is great you did your homework prior to traveling and it sucks that you got burned your first time out. Here is a bit more advice albeit too late: Always have 3 months of living expenses before traveling because you never know when something like this can happen unexpectedly. Good advice for a perm job as well, but very important for travelers as our assignments are short term, so something unexpected can occur much more frequently. Even experienced travelers get cocky and are burned because they didn't have personal resources to see them through, and believed that it could never happen to them.
Traveler books are great, but often paint a rosy picture without enough sound advice. A good place for sound advice is pantravelers dot org, a specialty association for travelers. Membership is free and there is a paid membership that provides legal support for contract disputes with agencies such as this one with an employment lawyer.
Traveling is great, and I hope you get a chance to find that out. Again, sorry this happened your first time out. One of travel nursing's dirty little secrets is that on average, one out of ten contracts fails. This includes contracts such as yours that never started. With good advice, your individual odds are much better than that, but sometimes something like what happened to you is unavoidable. Don't take it personally, no one did it on purpose to you specifically.