My sons1995 Hyundai elantra has a hole in the oil pan is this hard to change and is it expensive can it be plugged or something?

You can mix up some JB weld and put that on but the surface has to be clean, you should drain the oil pan first. I know as when I lived in OK my son said spin the tires and I did and a gravel hit my oil pan and by the time we got home I had not oil and #2 son cleaned it good and used Jb weld on it.