I joined a website design project for a client. I asked him to deposit 50% of the project's money. I sent draft designs; they were almost complete. Suddenly, the client said he met a financial problem and canceled the project. We didn't sign any contracts. I couldn't get the remaining amount while I think I deserve more than the 50% deposit. How do you handle cancellations?
With no contract, keep the 50% and move on.
If you want a "kill fee" you need to have that in a contract. It's difficult, if not impossible, to try and collect a cancellation fee after cancellation without something in writing. You can certainly ask for such a fee. But the client has no obligation to pay anything.
In addition, it's your responsibility if the deposit does not adequately cover the work needed prior to client review.