rif those are good little combines. My neighbor ran a 4400 for 15 years and had 6,500 hours on it when he traded. For both the table and the cornhead, if it is ready to hit the field $4,000 isn't too much. I would offer him $3,000 though.
I know of a guy who just paid $7100 for just the combine. 79 model 4400 diesel with 2500 hours. It was in nice shape. If your combine is in good shape, that is about what just the combine goes for. The heads are around 1500 to 3000 for corn head, and same for bean head. I saw a beat up 213 flex go for 1200 not to long ago. Sounds like a great deal!
That sounds like a good deal if its in any kind of condition. Around here a wide row corn head like that 444 would only be worth $1200-1500. The 213 header if its a flexhead and in good condition will fetch up to $2500. All around it sounds like a good price. Check the bolts holding the front castiron supports to the upper angle irons (just under the engine and cab). If one is broke or missing it is a good idea to replace it as that will allow the sheeting to flex more than it should which can lead to cracks. Also check the rear of the combine. The rear strawwalker hood is a unibody construction and if a chopper was run out of balance for to long it will start pulling and cracking the sheet metal where it bolts on. Deere made a brace kit which shores up the hood from underneath. I found one on a combine in a salvage yard and installed it on mine just in case. Those two things are the most common problems you will find on these combines. The rear hood is most serious and I would definately look that over.