At least over where I live, the 1 mg pills are inordinately expensive because there isn't any competition. The only brand available is Propecia, at about $70 / month, while generic 5 mg pills are something like $20 / month. Since the latter are marketed as a prostate instead of hair loss drug, depending on what is written on the prescription one may not have to pay all of it.
As Cynthialee wrote, pill cutters are readily available at pharmacies. On the other hand, there are rather severe warnings that bits of a broken pill must not come into contact with a fertile female, and even that a man taking the pills should use a condom when having sex with a pregnant woman. This, they say, is because even tiny amounts of finasteride can cause some intersex conditions in genetically male babies. I'd really like to see some estimates on how big the risk is...
With regard to the original article, it isn't too surprising. Oestrogen increases the risk for breast cancer, and 5-alpha-reductase blockers increase the amount of oestrogen (after all, if the testosterone isn't converted to DHT some of it will be converted to oestrogen instead). Whether the increase in risk is something to worry about is another matter, but for people with an already greater hereditary risk it may well be. Speaking for myself, a slightly bigger risk of breast cancer is a price I'm willing to pay for having breasts.
Nfr