<p>How much are you billed if you decide to register for another SAT subject test? Is it better to register early?</p>
<p>I think that I was billed $10 when my son decided to take an extra test.</p>
<p>As long as you sign up for one test, you can take 2 others (non foreign lang) on the test day and the CB sends you a bill afterwards.</p>
<p>I had my son sign up for one and then decide that morning if he wanted to take more. This way, if he felt poorly or something, I would not lose money as I would if he had signed up for 2 and left after one.</p>