That Holy Feeling

Lately I have been struggling with the issue of money and tithing to your church; how much should I give, how often, etc. Somewhere in the back of my mind I remembered hearing the "10%" thing, that you should give God ten percent of your income. The Scripture also repeatedly says that if you give God as much as he instructs, He will provide for you and bless you. So I sat down to do my finances.
Now, when God said ten percent did he mean ten percent of your gross income, or net income? After thinking about it I decided on net for some reason. The following is a layout of my finances for the first two weeks of June, keeping in mind that I need cash on hand for milk and gas.

Net income: $1498.57 (10%= roughly $140)
Groceries, tp, etc: $147.88
James' allowance: $101.80 (includes ATM fees)
Rent: $450
Water bill: $50.91
Dell: $32
Geico: $68.50
One Spirit (book club): $38.03
Colombia House (DVD for James): $26.75
Army (loan for deductible when we it a deer): $50
Eye doctor (LASIK eye surgery): $50
Furniture: $279
Capital One: $25
Orchard Bank: $25
Dairy Queen (our once every two weeks outing): $9.70

Now here's the kicker: All of those added up and subtracted from the net is -guess what?- $144. Which would be $140 (ten percent) for God and $4 for milk (which HAPPENS to be on sale at two gallons for four dollars). Is that amazing or what?!
But then I remembered: I need refills on my meds and gas money, too. Refills will be $18. Then God reminded me. James get hazard duty pay on June 4th in the amount of $25. So there's my refills with $7 to spare. Not exactly enough to get a sizeable amount of gas. Then God jogged my memory again: Mom owes me gas money for taking her to Miles. $5? So there's $13 for gas, and I don't plan on going out of town within the next two weeks, so that would be just right for two weeks of around-town driving.
Granted, that leaves my checking account balance at zero, but hey. God will bless me. Isn't He amazing?!!!