Do I just pry it off and stick the new one back on or what?
Any advice/comments would be very much appreciated!

what year is the car? does it have a center cap?(a round peice that covers is sperate form the rest of the outter wheel cover that goes over the lug nut location. if not then use a large flat head and go around across the hub cap inserting the flat head and gently twisting it should pop right off. When installing the new one make sure to line up the valve steam with the acording hole. tha is about it hust pust one side in hold your hand there and push the other and work your way around. if it is the center cap style that my require removing the center cap the lug nuts and then eather unscrewing the retaining screws located near the lug nuts or simply removing the lug nuts them selves and then poping the cap off in the same fassion stated above.

Thats about it

Thanks!

IF you have the wire wheel caps you should have a locking nu tholding it on, you would have a special key to remove it.

The base model regular cap just pops off.

He has the base wheels on a '80? Coupe Deville.

Yep, I got the hubcap off pretty easy and the one i had to replace it with was pretty scratched up, so i just replaced the centercap which was what needed replacing in the first place, it screws on... It was kinda tricky getting back on but with a rubber mallet, i was able to get it on...

It isnt in nearly as good as shape as the other 3 on my car (the other 3 are originals that look almost new, no scratches) but it will have to do for now until i can find a better replacement, or until i get rims...