I'm a tea drinker primarily but have come to love a cup of coffee during the day. I opted for a Keurig. While the machine was pricey ($99 on Ebay, free shipping), I get a pack of 12 cups for $7.49 which means that it's less than a dollar a cup. I get about 20 ounces from the K-cup (for me that's 2 mugs).
I drink decaf but have some caffienated for guests.