Ant:
For double aeration, charge what you would for a yard twice the size. For a 5000 sq. ft. yard, charge the 10000 sq. ft. yard price.
Anywhere from $5 to 12.50 per 1000 for a single pass are what I've been finding.
You may have to explain the added benefit of double aeration
and that the seeding will work better with the aeration twice or
even more.
The charge for seed will vary depending on blue, fescue, etc.
If it is a fix up type seeding, give yourself a little cushion
for a return visit. Stress the watering!!!!!!! The fact that very few customers do the amount of watering they say they do, results in landscapers making several return visits and getting into several arguments.
A starter fertilizer application will also help push the roots of your new seedling grass.
Hope this helps!