lose one freeze plug, lose them all. the correct tool for pulling a freeze plug is a slide hammer. you drill a hole in the plug, and then put the screw tip on the hammer and pull it out. You can pull one with a screw driver, but you run the risk of knocking it into the coolant gallery. Once one starts to leak, it will soon get a bigger and bigger leak, and on a hot day it will blow and you will be dead on the road. No doubt the cost of this repair has more to do with access to the plug than anything else, and you may well need to pull the engine out to get to the plugs. some engines have additional plugs on the end where the tranmission/transaxle mounts, and cannot be replaced without seperating the two parts. Put in brass freeze plugs instead of the cheep steel ones the mfg put in, and avoid this problem in the future. Now, just wait for these pros to tell me how wrong I am ha ha, as I am only a shade tree guy who hasnt had to do this job since 1977 on a ford pinto. anyway good luck to you.