another fire door

[slb9155]

I have a family room which originally was a garage. I need to put up a fire door because I am moving and per building commissioner, I have to convert it back into a garage. There is an existing (inside door) leading from the garage into the kitchen. Does anyone know how I can get out of this as cheaply as possible and stay within code. I also would like to know where I can purchase such a door. Thank you