When I bought my boat it had a hot foot on it which I like, but it broke. The boat it stuck in full throttle and the hot foot will move back and forth. Where can I get a new cable and how hard is it to change out? I have 1999 Skeeter ZX210c

It's pretty easy, just pay attention to how everything is set up before you start removing parts. You can remove the cowling and put the throttle back to normal. There are numbers on the throttle cable that designate the necessary length. Cabelas and Bass Pro should have them, as they are made to fit the engine make.
I suggest taping (securing) the new cable to the old to "fish" it through the hull.

Thanks

I put my Hot Foot in and when I did I left the one off the control box in just tied it up. That way if I am out and the foot cable breaks all I have to do is open the engine cover and hook up the one for the control box.

I did the same. I assume newer boats do not have the other cable. I almost removed mine when installing the hot foot, but quickly decided against digging into the control box and figured there's is no such things as too many spare parts on the boat.

Rockwall Marine should have them too or be able to get them.