For many of us, the start of a new year means taking steps to make some sort of personal improvement, whether it's our health, our appearance, or the way we spend money. The problem, however, is that some of these resolutions can come at a cost. And if you're not careful, you could end up paying a bundle to chase a goal you might otherwise accomplish for free.

How much will you spend on a gym membership?

Getting in shape is among the most common New Year's resolutions out there, but it's also one area where the media does too good a job of persuading us to overspend. The average cost of a gym membership is $58 per month, or $696 per year -- yet 67% of those who sign up for memberships don't actually use them.

Notebook with 2018 goals written on a sheet of paper

IMAGE SOURCE: GETTY IMAGES.

Though getting fit is a noble goal, you should know that you can do so without spending a bundle on a gym membership you may or may not use. For one thing, jogging is free, as are hiking and other such outdoor activities that promote a healthy lifestyle. Furthermore, if you have an old bike sitting around, ride it -- for miles at a time. Before you commit to a gym membership, see how well you fare exercising for free. If you're getting results, it means you can probably save close to $700 next year.

What would you pay to lose weight?

Up there with getting in better shape, losing weight is another popular resolution on many folks' list. (In fact, you might say the two go hand-in-hand.) But just as you don't need to pay a ton of money to exercise, so too can you lose weight without having to spend any cash.

Unfortunately, countless Americans don't buy that, or don't have the discipline to diet on their own. As such, those looking to lose weight can pay anywhere from a few hundred to a few thousand dollars each year for what they perceive to be necessary guidance. Weight Watchers, for example, costs over $400 a year, but that doesn't include the price of food. On the other hand, if you were to read up on healthy eating habits and portion control, and go it alone, you'd have that money available for more important things, like healthier groceries or smaller clothing for when those pounds finally do come off.

One New Year's resolution whose cost is well worth it

If another goal of yours is to save more money in 2018, you should know that it's a crucial one to uphold. Most Americans are behind on savings, with roughly 39% of U.S. adults having absolutely no money in the bank. Furthermore, an estimated one-third of workers have no money set aside for retirement, including those for whom that stage is rapidly approaching.

If you're looking to up your savings game next year, then you should know that it will come at a cost -- an opportunity cost, that is. This means you'll need to be prepared to spend less money on luxuries and the things you've come to enjoy if you want to sock more money away for the future.

The good news? It's a cost that's totally worth it. When you're sitting on a generous nest egg in retirement, you're not going to spend your days harping on the fact that you had to cut out cable in your 20s. So take a look at your non-essential expenses, see which ones play the smallest role in bringing you happiness, and work on reducing or eliminating them. And then give yourself a pat on the back for a job well done.

There are some New Year's resolutions that cost you money, and some that prompt you to get your finances on track for the long haul. Focus on the latter, and you'll have more to celebrate by the time 2018 draws to a close.

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