Developers do not, shall not and/or should not work for free.
And there is no such thing as “just do this tiny thing”
I do charge for my services (huge, small, or even tiny) what I believe to be a reasonable fee. You don’t like that? The market is full of other developers who probably are better and cheaper than me.
And no, sending an email stating that you agree to my fees is not enough. You need to send a down payment before I start working.
The final product will be showcased on my OWN computer and will not be deployed to your servers until I receive the final payment.
You cancel? No refund.