I have been on the depoprovera shot for over 3 years, which means it has been over 3 years since I've had a period!
I get a shot every three months, and it costs me about 75 dollars each time, so really, it is less expensive than the pill. I can't ever remember to take them anyway, so this works well for me! Disclaimer: it doesn't work out well for everyone, and when I first went on the shot it took about three months before the breakthrough bleeding stopped. But I lost a lot of weight when I first started taking it, mainly because I stopped taking the pill. Just my 2 cents! Your doctor knows what is best!