How do you replace a heating core for a 1997 KIA sportage is it expensive at a garage or even possible at home?

we just got done doing that very thing. It takes time, patience, and alot of cussing...lol. Take out the stereo...then the 4 nuts, two behind the stereo ...one on top and one on bottom. The other two are by the air conditioning fan. You then take the heater switches/and wires out. Take out the glove box and covers as well on the passenger side which will allow you room to manuever the parts out. The heater core comes out after you take the air conditioning fan...reminder take the ac out...seperate from heater core. You also need remove the hoses from the engine side. It becomes fairly easy from this point on.