I guess in reading this thread I don't get the OP.
OP - pray tell, how could you spend $100 / month on coffee (with the milk, etc being ON TOP of this)?
In coffee crazed Seattle, good, 100% Arabica beans can be had for the order of $10-$15 / lb. and pretty fair for somewhat less.
Unless you're drinking the cat crap coffee (
http://en.wikipedia.org/wiki/Kopi_Luwak) I'd find it hard to drink enough to spend a $100 / month on beans. I rarely go through more than a 4 pounds a month, and that's for 2 of us.
The "correct" amount is 21 grams per 8 ounce cup of drip.
http://stumptowncoffee.com/a-scale-is-not-just-for-coffee-geeks/21 grams (to the first order) is 3/4 of an ounce. So, per pound, that's about 21 cups of coffee.
The "correct" amount for a double shot of espresso is 16-20 grams.
http://www.home-barista.com/espresso-guide-dose-distribute-tamp.htmlFor an "order of magnitude" calculation, use 20 grams, 454 grams / lb yields 22+ double shot pulls per pound.
Say one allots themselves 2 cups per day, that would be about 10 days per pound, or about 3 lbs / month, for drip. At $10 / lb - only $30.
If one were a latte drinker, 2 double shot latte's per day would yield 11 days per pound, or a bit under 3 lbs / month, so a bit under $30.
One fact folks may not know: Good coffee (e.g. Arabica, the bean type used exclusively in all speciality coffee) has about 1/2 the caffeine of the crap coffee (Robusta, the bean type used in mass market pre-ground canned coffee).
http://en.wikipedia.org/wiki/Coffee The two most common sources of coffee beans are the highly regarded Coffea arabica, and the "robusta" form of the hardier Coffea canephora. The latter is resistant to the coffee leaf rust (Hemileia vastatrix), but has a more bitter taste.
Note: I have to admit that several years ago, I went to these guys
http://www.seattlecoffeegear.com/And bought a double boiler, semi-automatic, one group espresso machine, with a related proper grinder. All in cost, about $1,500 (more or less, the lowest cost "real" espresso machine for home use - 110v and water tank, in lieu of plumbed in and 220v). Its used every morning just about (unless on days like today when a pot of drip is made). Typically I'm making a latte for myself and another for the SO every work morning, and sometimes on weekends as well. Call the utilization about 10 lattes / week. See the thread where I've started making my own Torrani type syrups (just whipped up a batch last night.)