I have been with Wild and they are legitimate. They did submit me to castings and I did get auditions. They never asked me for 1 dime. They work off of commission.
Most casting is done on-line through sites like LA Casting, Actors Access, Casting Frontier. This of course means that casting calls are done on line and submissions are done on-line. Then you get auditions that are done in person and you take it from there.
I changed agents a while ago and wish I didn't. I got more auditions with Wild than I do my current agent. I changed agents just because I thought I might get more auditions, but the opposite was true.
It won't cost you anything to represented by them. You are always free to change representation if you want down the line.
FYI, it will be advisable to take a commercial acting class to increase your versatility. This is incase you haven't done so already.