I got mine pretty cheap, could'nt resist the price. we do some aeration, and I did/do still have a pull-behind one. Last fall we did more then we ever did before, may advertize somewhat this early spring. But in my case it was worth the investment. I have the turfco.
I was looking into buying one this last year, but I didn't want to fork over the dough for a good one. I went and rented it, I only had it 2 days, got all the jobs done, there is no way that it would be paying for itself right now>
I rented one once, and after that I decided it was time to buy. I bought a Plugr PL400 and it paid for itself and more the first season. If you buy one you should be committed to advertising and creating more business to get use out of it, otherwise if you just want to satisfy the needs of a few customers then I suggest renting.
I bought A used walk-bedhind bluebird model from the same place that I was renting aerators, I got it for a good deal and paid for 70% of it this fall. even if i dont advertise for it I figured it would pay for itself just not having to pay the rental charge every time I needed to rent one.