I never have really promoted a product or website here, and I hope it is OK? But, it is the "Dollar Shave Club" that I keep hearing about on the radio. If you sign up for their cheapest plan, they send you the razor for free, then 5 stainless steel cartridges for $1 a month, plus $2 shipping and handling, for a total of $3 a month. I know I spend more than this every month, and what guy doesn't forget to buy razors and end up using a dull ass razor for another week or so?
Don't know if this would be a good deal for a woman, I never kept up with how many razors they use? You could set up two accounts. You can also get new razors every other month if you like. You can cancel at any time.
Disclaimer: I have no interest in this company, I wish I did. I bet this guy is doing well.
http://www.dollarshaveclub.com/