If you own a car, then you probably know that it needs an oil change about every 3,000 miles or every three months—or if we're being honest and you're like me, whenever you remember. It's a necessity, so unless you know how to do it yourself, you'll have to take it in to a shop, which is probably the only time you think about oil change prices.

At Groupon, though, we think about cost a lot, and in 2016 alone we sold more than 1.3 million oil changes. We decided to dig into that number a little deeper to discover just who was buying all those oil changes and, more importantly, where you can count on getting the best deal.

On average across North America, oil change prices run around $46 and can cost upwards of $70 for premium oil changes, but with Groupon, that cost drops significantly.

Groupon customers can expect to spend only about $25 for a conventional oil change and about $55 for a premium full-synthetic oil change. Going a bit further, we saw that where you lived made a big difference in price, too, and the results were quite a surprise.

The highest oil change prices

While we would have put money on mega-metropolises like New York City, Los Angeles, and Chicago nabbing the top spot for the city with the most expensive oil change prices, none of the three even broke the top 10. Instead, the north-central Piedmont Triad region of North Carolina claims the title of the area with the most expensive oil changes, tied with Pittsburgh: $49 on Groupon. Cincinnati follows close behind at $48.

The lowest oil change prices

Similarly, when it came to a cheap oil change, smaller cities didn't necessarily always offer the lowest prices. To find those, it seems you just need to head to the sizzling South. Three of Florida's biggest cities all ranked in the top three, with Phoenix and Houston rounding out the top five, all of which are under $30 on Groupon. That makes a difference of more than $20 per oil change, and that's not chump change.