As the weather warms and gas prices soar, people begin trading four wheels for two to help save on fuel costs.

While spring is always busy for Cycle Works, 2121 Kasold Drive, the store was really hopping in the summer of 2008 when gas prices spiked to nearly $4, owner Gary Long said. He saw record-breaking sales monthly.

“And not just by a little bit,” Long said. “It was 45 percent.”

If you are looking to save money, getting on a bike isn’t always as simple or as inexpensive as you think. You have to find the bike that best suits your needs and then all of the gear that goes with it.

To help figure out just how much to spend and how far you have to ride to make the investment pay off, we’ve provided this bicycle-friendly guide.

To get you started

Regardless of how fancy the bike, all cyclists should be equipped with basic gear to keep them safe.

Helmets: $25 to $35

Matt Farnsworth, manager at the Re-Cyclery, 731 N.H., said that helmets are a lot more comfortable and less expensive than what they used to be. And, everyone wears one nowadays, leaving no excuse for why you shouldn’t. In fact, if you are under 18, wearing a helmet is the law.

Lights: $15 to $20

Another biking law is to have lights on at night. Bikes should have a headlight in front and a red reflector in the rear. Dan Hughes with Sunflower Outdoor and Bike Shop, 802 Mass., recommends using red blinking lights in the back to more easily call the attention of the drivers behind you. Even for cyclists who think they will never bike at night, Farnsworth said it’s something that should be put on just in case.

Water bottle: $5 cage and $4 to $10 for a bottle.

Having some form of hydration for the bike ride is a good idea, especially if you plan on biking during the hot, humid summer.

Locks: $15 to $25

If you plan to leave your bike in public places, a lock wouldn’t be a bad idea. Bicycle theft is a pretty common crime in Lawrence.

The ride

$100 to $250

You won’t find any new bikes at Lawrence cycling shops in this price range (although you will at large national retailers). The best bet is looking for used bikes.

At the Re-Cyclery, used bikes start around $125 to $150. This week, the Re-Cyclery had a 1994 red Takara cruiser on sale for $125 and a 90s model Giant Option for $225.

To find anything cheaper, check out Craigslist. Last week, a quick scan on the website showed a number of bikes for sale in the $50 price range. If you buy a used bike online, Farnsworth advises buyers to make sure to find a bike that fits.

After buying the bike, it would be a good idea to get it checked out by a local bike shop. A simple tuneup costs $35 at the Re-Cyclery. For bikes that need new tire tubes, brakes and cables, the cost will be more like $60.

$300 to $400

For less than $300, Long doesn’t think you can buy a quality new bike. At Cycle Works, Long suggests starting off with the versatile Giant Boulder, which is priced at $309. He also has a comfortable city cruiser bike priced at $379. Over at Sunflower, mountain bikes start at $320.

$400 to $500

For cyclists who are mostly interested in commuting, Hughes recommends a road hybrid bike. Road hybrids have thicker tires than road bikes but taller wheels than mountain bikes. At Sunflower, road hybrids start at $429.

The bells and whistles

We didn’t check on the price of whistles, but at Sunflower, bells start at $5. But that’s not all the gear and gadgets you can buy that will make your ride more comfortable and fun.

Baskets: $20 to $40

At Re-Cyclery, you can also buy used baskets and racks for $5 to $10.

Panniers: $30 to $40; pannier rack: $25 to $30

Panniers are great for carrying groceries, clothes or work supplies. They can be slung over a rank in the back of your bike.

Fenders: $30

Fenders prevent mud and water from splashing up off the back tire. This will prevent a strip of brown from forming on the middle of your back when roads are wet.

Flat tire supplies: $14

The cold, hard truth of cycling is that one day you will get a flat tire. To keep from pushing your bike home, here are some supplies you should bring along: levers to remove tire ($3), new tire tubes ($5), patch kit ($3), air canisters to fill tire ($3).

The payoff

The real question is how far would you have to ride before your investment pays off. To do the math, we looked at the fuel efficiency for the average car (25 miles per gallon) and the current cost of fuel in Lawrence ($3.39). Here’s what we found:

$150

In this price range, you could snag a bike off of Craigslist, get a tune up and all the basic start-up gear. Before your investment paid off, you would have to pedal 1,106 miles.

$400

For about $400, you could buy the lowest-priced brand new bike at Sunflower or Cycle Works and still be able to afford all the basic start-up gear. However, you won’t start saving money until you have ridden almost 3,000 miles.

$600

For around $600, you could purchase the road hybrid bike, the basic safety gear, a basket or pannier and rack, flat tire kit and fenders. In just 4,425 miles, you will have biked enough to pay off the cost.

It should be noted that many would claim the biggest benefits of biking aren’t the economic ones. Biking provides exercise, cuts down on traffic congestion and carbon monoxide emissions, and saves on the wear and tear of the vehicle.

Oh, and did I mention cyclists usually get rock star parking?