This is a rough estimate but if you take the general rule of thumb of changing the rod every two gallons the math works out like this.
Red Dot $180.00
Nova Plus 12-3 ct $350.00
Change the rod twice in each motor and you come up with
$260 total for the Red Dot over 5 gallons or 18 liters.
$410 total for the Plus 12-3ct over 5 gallons or 18 liters.
For someone just getting into the hobby and they are trying to save some money, a Picco motor would be the way to go. They are fast and from what I've seen they are also durable.