It wouldn't be $100 or $300 though, unless each and every one of those vaccinated were to get the disease. My understand that the disease becoming cancerous is rare, and it's still possible to prevent the presence of a rare persistent infection from becoming cancerous by catching it with Pap tests and making treatments. 80% of women by the age of 50 are figured to have contracted the disease, but the pervasiveness of cervical cancer seems to dwarf that (and the rates of cervical cancer have been continuously falling since the 1950s as it is, thanks to the Pap test.... link) However, according to the Alberta Cancer Board, cancer can be prevented and treated if detected early.
But even then, lets say 1 in 10 women will actually get cervical cancer, then the cost goes to $3000 to cure someone. If it's 1 in 100, then the cost goes to $30000, 1 in 1000 becomes $300,000 to save a life, because fortunately, the vast majority of women will not have to worry about being unable to fight off HPV naturally.
I'd much, much, much, much, much, much rather they spend millions of dollars on this which explores using DCA as a potential cure for cancer, but will not be receiving any funding from pharmaceutical companies because it involves a compound which is not patented, and therefore will not be able to recoup the heavy costs of clinical trials. I'd see this as being more useful allocation of government funds than spending millions of dollars (and making a pharmaceutical company that doesn't want to fund something that may be more widely useful and would compete with their own, limited scope project) to save a small amount of lives.