How do I tackle the question of "What is your expected salary?" in job interviews? How do I know what is too high or too low?

Unless it is your first job.
Or you are changing fields.
Or you are not doing well in your current role.

Always consider 15 to 20% increment.

1) your current role is paying X amount because you deserve it.

2) you are moving. New role new responsibility. It is to cover the change.

3) you could stay and get increment and others anyway. So it is to their advantage to move you.

Note that you also have to consider if you might be currently underpaid.

Fully relying on salary guides is also risky as they are often only correct with context.

My response to this question is

“can you Let me know the Budget for the role?”

If the answer is “we are open”

as The others mentioned you need to do your home work and counter with

”I am expecting xxxx-xxxx”