river stone price is around $80 /yard, most of them charge you one yard even if you only take half yard.
there is one at river road, they can charge at half yard.
If you have a truck or tow package, it would be easier. Some one said One yard is around 2000 lb, some one told me is 1.3 Ton.
If you do not have truck, it may be more expensive for delivery.
I rent pick up from enterprise to buy gravel, each time can load half yard, but I still have to pay one yard. My experience is, if you need two yard or more, it is better to let them delivery if do not have access to a truck.
You can check kijiji, or yellow book.