Lantus Solostar Cost Information. The price of Lantus Solostar insulin delivery system may vary depending on pharmacy or online store. A kit containing 1 carton (5 Solostar pens) of Lantus 3 ml can range from $290.63 (with coupon) to as much as $299.69 (with coupon).o avoid skin irritation issues, change the location of the injection site daily. The price of Lantus Solostar insulin delivery system may vary depending on pharmacy or online store. A kit containing 1 carton (5 Solostar pens) of Lantus 3 ml can range from $290.63 (with coupon) to as much as $299.69 (with coupon).