The only way to use the authentic Pro-Q 3 for free is through official channels:
His mouse cursor moved on its own. It drifted toward the folder. Toward the two years of work. Toward the best thing he’d ever made. fabfilter pro q3 free top
If you are a student, FabFilter offers a very "top" tier educational discount (usually 50% off). If you time your 30-day trial with a month of heavy mixing, you can finish an entire album using the "free" software before the trial expires. The only way to use the authentic Pro-Q