I guess it depends why you want it. I can understand people getting it for accidents and injuries but other than that I'm not so sure. Usually insurance plans don't cover diseases common to a specific breed or congenital defects.
So that leaves out just about 100% of cases of luxating patella, liver shunt... If you went with just an accident plan it would probably run about $15-$20 a month. That is $240 yearly. In five years that is over $1000 and you may not have to deal with an accident in that time, so you've spent it for nothing. I would just save up what you can and if there is an emergency you can always use care credit. I see people on here list what they got back from insurance and what they pay in monthly. It doesn't look like a deal. I am still looking into it though.