That is an exhaust based ventilation system and while it is allowable, it really is not the best type of system to use.
A simple ERV or HRV is not that costly at all depending on the setup you get and just how "finished" the house is. I have seen homeowners that have installed one for just under $300, while a more typical install price starts around $500 and can easily climb into thousands.
The biggest catch is do you really need it? Does the house feel stuffy? Are you always inside? Or running in and out? How many people are there? Etc...
One other issue is what type of water heater, stove, and heat system do you have?
For more information:
Read "How can you add fresh-air ventilation to an old home with a forced-air system and only supply ductwork throughout?" a Q&A answered by Danny Kelly.
For more on the types of ventilation and some of the issues with blanket measurements read Sean's blog post here.