What is the likelihood you will be sued to collect a 500 dollar debt from a credit card?

At a minimum, it depends on the following:

What the laws of your state allows through the courts: (liens against property, wage garnishment, etc)

If the laws of your state allow such outcomes, it will be up to the creditor to decide if pursuing you in court will adequately serve their purposes.

If you have no assets or job (i.e. you're 95 years old and are in a protected income status (social security recipient) the creditor may go for a default judgment against you. A default judgment will stay on your credit report for 10 years. (but if you're 95, that is the least of your concerns)