Fire pits are a great way to bring friends and family together. They cozy up a yard and add both a romantic and “togetherness” element to your outdoor space. There are a lot of different directions you can go with a fire pit. Fire pits can vary a great deal and are built in all different shapes, sizes, materials and styles.
Be sure to check into building regulations and codes before starting. You must be at least 25 feet from your house, and there are other regulations as well. Be sure that you have thoroughly researched the building codes in your area and that you are within regulation.
Crusher Cone- You can use an old crusher cone from a concrete factory or a rock quarry. Often, when their crusher cones are worn down, and they are discarding them, you can buy one from them for very inexpensive, or even pick one up for free. Bury it a few inches in the dirt and stabilize the crusher cone with cement or gravel. These make really great fire pits and you can do this for relatively inexpensive.
Image from Landscaping Network.
Stone- Stone fire pits are very popular and very aesthetically pleasing. They look really great and are very stable!
Image from The Clymb
River Rock- A fire pit with river rock is also a very nice and inviting look. This is also an easy DIY project. Design your shape, and create a concrete structure in the shape you want your pit (usually square or circle.) Place a fire bowl in the middle and fill in the shape with gravel. These are fun because you can be creative with your concrete and the color of your rocks.
Image from Sahm One
Natural- Some people prefer the natural look for a fire pit and want it to look more like a part of nature. This is great because it blends in perfectly with it’s surroundings! 
Image from Decoist
If welding sounds better than digging a hole. This idea is for you! This is super modern and would look great in my backyard. Here are the instructions from The Brick House.
Glass Box- I love the look of this. Not only could you incorporate this outdoors, but you could do this inside as well! Full tutorial from The Art of Doing Stuff.
Wheelbarrow- Channel your inner artist with this great fire pit. You could also do this with other things! Idea from here.
These are just 4 of the most popular DIY outdoor fire pit ideas. You have many options. You can also make a fire pit that uses natural gas. Pavers can also be used around a fire pit. Before you start, design your area, do your research and choose one that will best suit you and your outdoor space.