How much would it cost to get my canines filed to a point, like vampire teeth?

What you are referring to is called reontouring.  Not sure why you would want them filed to a point, but set up a consultation with a local dentist to see if they will do it for you.  This typically will not give the most aesthetic appearance, but perhaps you are not looking for that.  Good luck.  

i have done this a couple of times, and i think its depending on each patients bite, if you have a regular bite, or overbite , or overject, but there si always a solution, more than be filed down there are some ways to make them aesthetically nice, searching for  that solution that you are asking, that they can look in a vampires canine teeth.on dental tourism you can find , plenty of options on this.