Adding Power Locks and Keyless Entry

Hey guys, newbie here...

I have a used 2004 Cavalier LS that doesn't have power locks or Keyless Entry. What would be the cheapest way to get these in there? I know little about cars so i wouldn't be installing myself.

Thanks

Sorry if this bothers you but just as a fair warning its a bitch to do.... and will not be cheap i would honestly suggest just getting new doors with power locks off a car in a junkyard that is the same color for cheap i have done it before and it works great all that has to be added is the wiring for it going into the doors and as for the keyless entry i dunno i didnt add that too but i assume it will be the same way as any other keyless installation i hope i have helped in some way

dave