I churn through 100+ bills a week. I'm single, I don't have children who live with me, I'm not a big spender, and I'm not a commercial Georger. Here's how I do it. Every bill mentioned here is entered and marked in my usual fashion.
Gasoline - I buy my gas $15 a time, using just marked ones. I have to buy gas more frequently (especially when the price is $3-4/gallon), but it's worth it to get more bills in circulation.
Groceries - Likewise, I buy groceries in small quantities. I stop at a store after work and buy a few items. It's generally no more than $15. I buy household items, clothes, and other Wal-Mart fare the same way.
For small purchases, I recommend using a dollar store (Dollar General, Family Dollar, etc.) rather than Wal-Mart or a large grocery store. Dollar stores generally don't take credit cards, so customers are far more likely to use cash. More importantly, people do not make large purchases at dollar stores. They buy only a few items. At a grocery store or Wal-Mart, the typical customer purchases a lot of items at one time. The smaller the purchase, the more likely the customer is to pay cash. The larger the purchase, the more likely the customer is to write a check or use a credit card. Thus I believe that your bill will probably go back out quicker at a smaller store.
Dining Out - I always pay for my meals out with ones. Maybe a few fives if I'm buying for my date or it happens to be large. If it's less than $15 total, though, I usually pay just in ones. I make sure to tip. (I once delivered pizzas so I know the importance of tipping.) I put the money in the tray or wallet, hand it to the waiter, tell them to keep the change and leave.
The cheaper you can eat out, the better. The lower the average cost of a meal, the more likely it will be paid for in cash, so cheaper restaurants will circulate more money. Always pay with ones in these places.
Bills - I have paid for my city utilities at city hall in fives and ones. When I was able to pay for my electricity at a retail store in town, I did that in cash as well.
Services - I pay my barber, chiropractor, dentist, and doctors in cash and get a receipt. For all of these I use ones and fives if the bill is low, and add tens or twenties if it is higher.
Car Maintainance - If I pay to have my oil changed, I do it in fives and ones. If I need other service on my car and it's less than $100, I'll pay cash. (There's not as much benefit from EMS'ing large bills and I can rack up points on my credit card.)
Car Accidents - OK, I don't recommend getting into an accident or committing a violation that results in you paying a fine. But if you do, pay for it in cash. The police department usually just takes cash anyway. Pay for it in twenties, fives and ones.
Coins - I always spend an even amount of dollars and get change back, even if the total is only a few cents above the dollar. By rounding up to the dollar you get another bill in circulation. Save your change. When I have "enough" change, I bring it to the bank and exchange it for one-dollar bills. (Note: This is also a good way to get into the habit of saving money.)
Coin Machines - If I come across a machine that gives you quarters (or other change) for bills, I put a few bills in it. I can exchange the quarters back for bills at the bank. Some places you can find quarter machines: game rooms, rest stops in some states (e.g. Michigan).
Entertainment - Movie theaters, bowling alleys, and video stores are great places to spend ones.
Casinos - I'm not much of a gambler, but I have used casinos to circulate bills. I generally don't care for slots, but if I do play, I play penny slots that have 9-40 paylines. I can put up to five $1 bills in those machines and get plenty of play. Once those credits are gone (or I happen to hit a nice win), I move to another machine. (By the way, casinos are also a good place to get any number of $1 bills, and unlike banks they are usually open 24 hours a day.)
Alternate Spenders - Tell your closest friends and family about your hobby and ask them if they will spend your marked bills. Don't be shy; tell all of them. Odds are that some of them will be glad to help you. Exchange their unmarked money for your marked ones. The more marked ones you can give them, the better.
When you dine out with others, offer to pay the bill and have everyone repay you. Odds are, in addition to paying more bills for the meal, your dinner companions will need for you to make change for their larger bills.
If someone you know is having a yard sale, offer to provide them with bills for change, since they will need to have a lot of bills on hand to make change during the sale. After the sale, ask to mark all of the unmarked bills that they have. Go ahead and get coins for them as well. You can give them the change that you aren't spending at the store.
You can use the same strategy at retail stores that need bills. In short, be a human change machine. (There are Where's George enthusiasts who have become the go-to cash people for friends, family and co-workers.)
Denominational Considerations - Get straps of ones from the bank. Keep at least $30 in fives on hand at all times. If you must get money from the ATM, mark it before you spend it.
I like to get ones from supermarkets and big-box stores. I go to the service desk and ask if I can exchange a twenty for ones. Almost every time they will gladly do it. The bills I get from doing this are usually in good condition. Many times I get new bills this way. Enter and mark the twenty first. Since you're exchanging only one at a time, you aren't dumping.
If you want to get a lot of bills in circulation, avoid spending twenties, fifties and hundreds directly. These bills will not circulate very well. Enter and mark any that you happen to get, but spend these bills by exchanging them for smaller bills. Again, exchange them individually to remain within the rules.
I generally avoid using two-dollar bills. If you are trying to get a lot of hits, using a $2 is not strategic. Twos have a low hit rate, and why spend one bill when you can spend two ones? (Nothing against those who like spending $2 bills. They just don't fit my strategy.)
In short, use every opportunity you have to spend marked ones. Use larger bills only if needed.
