Whether your goal is to make your money go further, save up for a big purchase (like a home), or just establish a comfortable financial future, saving money is a good idea. And for the most part, any effort you make to save money is a good thing. Paying less for a product or service, eliminating unnecessary expenses, and restructuring your budget will help you accumulate wealth that you can then use to invest in your future.

However, some allegedly "money-saving" habits may work against you, costing you more money in the long term.

Though these habits seem like they might save you money, they could ultimately cost you more than if you hadn't pursued them:

1. Driving your old car.

Buying a new car would cost you a lot of money, so you might as well drive your old junker around for as long as possible, right? In actuality, driving an old car could end up costing you upwards of $1,000 a year in additional expenses, such as repairs, safety improvements, and insurance--not to mention the extra environmental impact you'll make in the process. Even if it costs a few thousand dollars upfront, it's often better to invest in a decent-quality, relatively recently manufactured vehicle.

2. Buying sale items.

When an item is on sale, you'll be more tempted to buy it; after all, if it's 30 percent off, you must be saving a ton of money! The truth is, many stores use "fake" discounts to drive sales. They may advertise a deep discount, but the discounted price still reflects the suggested retail price, and the store will be making the same margin. It only looks more attractive, and only looks like it's saving you money.

3. Buying cheap clothing.

Clothing can be expensive, but in general, you get what you pay for. High-end designer brands are all about style and aesthetics, but most moderate-to-expensive pieces are priced because of the quality of materials and manufacturing involved in the process. Buying cheap clothes at a local discount retailer might save you money in the short term, but those clothes will fall apart or fade much faster than those you bought with a pricier initial investment.

4. Keeping your money in a savings account.

In many consumers' minds, a savings account is the best place to store savings. However, the average savings account yields an abominable 0.06 percent interest rate, which is much lower than the rate of inflation. You're probably better off putting that money to work for you by investing in stocks or bonds, or looking for a higher-yield account to keep it in.

5. Adding products to nab free shipping.

We've all been in the position of having $42 in a shopping cart, when $50 or more could earn you free shipping. In the moment, it might make sense to find an $8-10 product to tip the scales in your favor--but if shipping only costs $4, you'll end up paying more than you wanted to. Sometimes, opting to pay for shipping, or waiting to place your order until you have another necessary purchase to add, is the better decision.

6. Avoiding health checkups.

You might avoid going to the doctor annually, or attending dental cleanings regularly, because you don't want to spend the money--even if you have insurance. However, those regular checkups have an important purpose; they're designed to catch harmful conditions and potential problems early, which means you'll not only have a better chance of dealing with them easily, you'll spend less to treat them. This is one decision that isn't just about your finances; it's about your health.

7. "Investing" in an extended warranty.

Extended warranties seem like a good deal; for a fraction of your initial purchase price, you can protect your device or product from damage, decay, and corruption for a specifically defined period. But almost universally, extended warranties aren't worth the money. There's a reason salespeople push so hard to get you to buy them.

Scrutinizing Your Choices

Just because a decision seems like it's saving you money doesn't mean it is. For all your money-saving and money-spending decisions, take the extra time to project your eventual costs, savings, and losses; you might be surprised at what you find. Most financial decisions are more complicated than they first appear.

However, this shouldn't stop you from making changes to your existing lifestyle. Even if only 80 percent of your money-saving decisions end up saving you money, you'll end up ahead of the game. Nobody is a perfect financial decision-maker, but with experience, your decisions will eventually get better.