I would imagine the car still needs to be aligned. 7 hrs is a long day for those 2 items, but it was probably done without a lift. $20 - $30 per hr is a fair rate, but I would ask him how much you can pay him. Let him put a $ amount on it. $200 should be the limit. The most important thing is that the work is complete and remember to get the front end aligned.
Depends on your relationship with your neighbor. I would do it for a 12 pack of good beer for certain neighbors, wouldn't touch it for others. I'd do it for free for family/friends, long as they kept me company. Trying to help someone you hardly know who took 7 hours would be worth $200 as a nice gesture.
I'm firmly with Duke58. This is a hobby for most of us. An Alfa car buddy is a valuable thing. Chalk up a couple of drinks, trade 'em back when you need some help on your Alfa (bleeding brakes, anyone) sometime.
I think I'll go with $150, may be $200. He's a great guy and it was a lot of work. I used to buy a couple cases of beer, but his wife got really angry last time. And Yes.. just got an alignment! The car really needed it despite the fact that I was so careful putting everything together.