If you really want to save money, Walmart brand Stay Awake caffeine pills are 80 200mg tablets for a few bucks. I split them in 4 so it is like 320 50mg servings for a few bucks.

The best thing about caffeine pills is you can actually know how much caffeine you are getting. I limit myself to 100-200mg a day. I wouldn't even want to know what I use to take drinking coffee but it was quite a bit. I will just drink coffee now as a treat.