.............

Let's go with TowerPro a popular cheaper $$$'s brand:
https://www.unitedhobbies.com/UNITED...idProduct=4899 - Motor - $14.55
https://www.unitedhobbies.com/UNITED...idProduct=4860 - ESC - $11.75
http://www2.towerhobbies.com/cgi-bin...&I=LXKX39&P=ML - Connectors - $3.09
http://www2.towerhobbies.com/cgi-bin...?&I=LXZK96&P=0 - Propeller - $2.79
Let's just assume the same, one already has a battery, charger and balancer

- grand total -
$32.18