I found no free resources when I was about to take it myself so if you are going to pay anyway, you might as well study and then go take the exam because then you see the questions. If you fail, you can take it again the next day but with a better idea of what they will ask.
Some questions I got and still remember were how close you can follow an ambulance and what is the speed limit and the period of time you have to follow it in a school zone. For sure they will also ask about the meaning of some signs and some speed limits on certain roads and for example what the parking lane on the highway is for.