I blame it on my friend Kathleen that I caught the sneaky savings bug. One day, years ago, she told me her secret. Whenever she wrote a check, she’d enter an incorrect amount in the register by rounding up to the next dollar — sometimes five. Once a year, she’d reconcile her account and discover, to her utter joy, enough “found” money in the account to pay for Christmas. Brilliant!

Saving money in sneaky ways is all about timing and discipline mixed with a healthy dose of courage. It’s learning how to fly under the radar to save money in ways others might not think about. You have to pay close attention and read all of the fine print, too.

GOOD ROOMS, CHEAP

Don’t call the toll-free reservation number when you need to book a hotel room, advises travel expert Peter Greenberg. You’ll speak with a reservations operator who has no wiggle room to give you a discounted rate. Instead, Greenberg recommends waiting until Sunday around 4 p.m. local time to call the hotel directly. Why? Typically, that’s when the hotel revenue managers who usually set and control the room rates are not working. Ask to speak with a manager or supervisor. Now you have the ear of a person with whom you can negotiate the price.

DEALS ON MEDS

These days, the high cost of prescription medications is enough to make you sick — even if you have insurance that picks up some of the cost. Here’s a little-known tactic to whittle down the price. Before you go to the pharmacy, go to the website for that medication to check for coupons and rebates you can use to reduce your copay. An example: the Nasonex website offers a printable coupon for up to $10 off, and you can come back every 30 days to print out an additional savings coupon for your refill — up to $120 a year with the Personalized Savings Program. Lipitor also has a similar offer. You may have to click around the site to find the deals, and offers can change frequently, but being diligent and checking back often can save you hundreds.

NEW CAR HOLDOUT

To get the best bargain on a new car, be patient, says James Bragg, auto expert and founder of car buying and leasing company Fighting Chance. The best week of the year to make a great deal is the week between Christmas and New Year’s. It’s the end of the month, end of the quarter and end of the year — and these are all aligned for the only time all year. Also, dealers are much more flexible about pricing. It’s the one time that you’ll get in on a car buyer’s rock-bottom market!

WHACK THE INTEREST

Take a load of interest off your home mortgage and pay off your house years early by adding one-twelfth of a mortgage payment to your principal each month. As long as you do not have a prepayment penalty, the lender will accept more than the required payment and will apply this to the principal, per your instructions to do so. Refer to this amount as a “principal prepayment.” This may not seem like much, but the effect is huge. Every 12 months, you’ll make the equivalent of 13 mortgage payments — one extra payment a year.

Here’s an example: Let’s say you bought a house for $170,000 at a 6% interest rate fixed for 30 years. The monthly payment is $1,019.23. One-twelfth is $84.94 — the amount you’ll pay each month in addition to your regular payment. Sticking to this plan, you would pay off your 30-year mortgage in 24 years and five months, and as a bonus, you would save $41,746.69 in interest charges.

Would you like more information? Go to Everyday-Cheapskate.com for links and resources for recommended products and services in this column. Mary invites questions, comments and tips at EverydayCheapskate.com, “Ask Mary.” This column will answer questions of general interest, but letters cannot be answered individually. Mary Hunt is the founder of EverydayCheapskate.com, a lifestyle blog, and the author of the book “Debt-Proof Living.”