I have not done enough jobs with spreading stone/river rock etc to get an average time to complete a yard/ton or whatever. I have figured mulch at $50 a yard labor. A condominium unit we are contracted has asked for a quote to take up all mulch, (takes 30 yards at roughly 1"-1x annually) then replace with the standard flagstone river rock (each rock is about the size of a handful) I don't think they really know the cost of the rock alone is expensive let alone how heavy it is and how much labor it will take - but in case for some very odd reason they decide to go through with it, I don't want to short myself. Does anyone have a set price for price of a yard of river rock? I can estimate how much in materials but again no set price for labor like I do mulch to make things easy....Thanks for all input!