storage unit cost
1 According to Answerbag.com, the monthly cost of a storage unit depends on the size of the unit. 2  For instance, a 5 x 5 foot storage unit costs around $40 to $50. 3  A 10 x 15 foot space runs around $75 to $150 and a 10 x 20 foot storage unit costs around $95 to $180. For instance, a 5 x 5 foot storage unit costs around $40 to $50. 2  A 10 x 15 foot space runs around $75 to $150 and a 10 x 20 foot storage unit costs around $95 to $180.