Online ACT test prep Recommendations

<p>My son got a 28 on the ACTs without studying. Now he wants to see if, by studying specifically for the test, he can raise his score on the December test. He says he'll consider online test prep and prefers that over a book, because the books are often so thick they seem overwhelming.</p>

<p>I'd love it if anyone can recommend an online test prep that they believe was effective and worth the money....say anywhere from "free" to a couple hundred dollars.</p>

<p>Thanks in advance for any input.</p>