Ball Joints are about $50 a piece for stock, those will be fine unless you are lowered, in which case you'll be better off with something like Steeda X2's, which also require getting their bumpsteer kit. Easy to replace yourself, you'll just need to rent a removal tool from the auto store when you buy the joints. Simple as raising the front end, removing wheel, pushing out the old joint, pushing the new in & greasing it up.
Tie rod ends would be similar price (Bump steer kit IS tie rod ends, will replace stock tie rod ends). Easy to install as well, however this messes with your steering, it is a good idea to AT LEAST have your toe checked if not getting a full alignment, and you'll have to install these the same way the stockers were on to ensure proper alignment.
And I would say that it's probably not the rod ends, ball joints on these cars and Ford in general go out, the boot will get damaged and it won't be able to hold grease, so you get metal on metal contact and thus the noises. You can easily check to see if they are still good by removing the wheel and just looking at it. Check out all other bushings and seals on the steering rack and front suspension.