There are many sources you can get blueberries from in Michigan. At the grocery store you should expect to spend no more than $2 a pint, often less during the peak season. Right now, Meijer has a 2 pound container of blueberries for $3.99.
You can also find blueberries at your local farmer's market. You will pay more money there, often around $4 a pint, but they will be better quality than what you get at a supermarket.
The best option for quality and price is to pick your own blueberries. Typically prices run from $1.60-$2 a pound. This way you get supermarket prices and farmer's market quality. Each week throughout the blueberry season you can find weekly updates on the blueberry u-pick farms in Michigan. Click here to read my latest u-pick updates (includes other fruit besides blueberries).
Looking for a way to use up some blueberries. Check out my recipe for homemade blueberry lemonade. It's delicious!