Are you listening, Turfco Bob? Someone should invent an aerator that would pulverize the cores so that you could aerate and topdress in one step. And if possible apply seed after the aeration and soil pulverization.[/QUOTE]
an option similar to what Riggle said above would be to aerate then let the plugs dry for a few days and then drag a chainlink fence to break them up and disperse. This will not work as well as top dressing with sand but would cost much less. I did it on my own property and it worked pretty well. I then over seeded and ran a poly roller with just a little water in it (just to get seed into soil not to recompact the lawn you just aerated). Double up the chainlink fence take a 10ft piece and fold it in half to get a little extra weight it will break them up better. Not sure if this is an option but figured I would throw it out there. Otherwise good luck I know someone on CL in my area offered rental of a topdresser last summer and it was very pricey.