We have an Ariens 624 that was purchased new, in 2007, for around 800 dollars. It runs well, and starts easily. I always turn off the fuel valve and let the engine run until the carburetor is dry. That helps keep the carb clean and in good working order. This snowblower is pretty heavy, and will not fit into the trunk of our car, so it has never been back to the dealer for maintenance. I do all the maintenance at our house. Fair price on a used snowblower depends on condition. You would have to start it up, engage the augur, and make sure the impeller is turning. The clutch and drive system would need to be checked as well. Make sure the snow chute can be turned. I would likely be willing to pay $500.00 for a used snowblower if I was convinced that it was in good condition.

"Fair price on a used snowblower depends on condition."
and model, size, and location..

Around here, (western NY) a "compact" Ariens like the 7524 is a "light duty" machine, and in less demand than a "full size" machine..and so prices would be lower..

but in areas with less snowfall, it would be a "normal" machine and would command a higher price..
I have also found that prices are higher, in general, for used snowblowers around the larger North-East cities..(Boston, New York city, Philly, etc) than they are in the "snow belts" of Western NY and the Great Lakes areas..where used machines are common as dirt and thus prices are generally lower..So, a lot depends on where you live!

based what you posted (and not factoring in location) I agree that $350 to $400 is a good starting place..maybe $500 in Boston, but thats going to be an unlikely selling price..

Scot