Overall, onions can cost from $1-$5 per pound. At Gofreshfruitshop.com, red onions are sold at $2.99 per kilo while brown onions are at $1.49 per kilogram or $2.99 for a two-kilo bag. Scallions or green onions are sold per pound or by bunch. The average cost of a bunch can be around $0.50 to $1. Some states sell onions per pound and the price can run from $2 to $3 per pound. This makes the price of each bunch to be around $1.50 to $2.00. The same price range can be applied to yellow onions.