2009 F-150 5.4 eng costs $800 to 1000 to change spark plugs - no garuntys - what is the best replacement pg?

What is the best replacement plug and should Ford carry some of the cost?

You have the 3 valve 5.4L. It takes a special spark plug. The OEM plugs have a two piece design that is prone to breakage. Champion makes a one piece plug for this application that solves this problem. There's also a very specific procedure for changing the plugs that Ford recommends. Part of which is hitting the old plugs with penetrating fluid and letting them sit overnight before removing them.

Find another shop. Changing plugs on those engines isn't the easiest job but its even doable by many DIYers with some basic tools. I recommend only Motorcraft double platinum plugs since that is what the engineers designed it for. The two at the rear are the most difficult but from experience I can tell you that any decent mechanic should be able to do them all in a couple of hours. $800 to $1000 is way too high. Plugs are a wear component, the warranty on most is 3 yrs/ 36k miles, unless its extremely low mileage its not likely Ford will help with the cost. I'm guessing that if you're changing plugs the mileage is a lot higher since the recommendation is 100k

Oh, good Lord. Just ask one of your neighbor's teenaged sons to go to the parts store and have him pick up the new plugs and socket wrench if he doen't have one. Make sure he gets the one-piece plugs. Go back home and let him install the plugs. When he's done in fifteen minutes, go buy him a 6-pack of his choice, and thank him for the help. You're all done, and your wallet will be about $100 lighter.