I've wanted to start my campaign for a long while now but I've never gotten to it because I have never been a DM. I don't own any of the books and I don't know if there are certain things I should be aware of or consider. If anyone has any useful links or tips/ tricks I could use I would appreciate it. Also, I don't have much money but if I want to become a DM is it necessary to own books? I don't any of them but I usually find information online or from friends/co-players who know the game or have the books

If you can purchase one thing. Or acquire it somehow, someway. Get the adventure: Lost Mines of Phandelver. It is a nice easy adventure to run and you can study it yourself to learn how to create your own adventures. 

I would suggest starting here: http://www.wasd20.net/resources/beginners-guide-to-dd-5th-edition/ and reading the Buyer's Guide 

Nope, you don't need to buy any of the books. All you really need is the Basic Rules which you can find here as a pdf or here on DnD Beyond.

Other helpful items:

• Go here to find printable character sheets as well as pre-generated characters that you can have the players choose from.
• The YouTube channel Don't Stop Thinking has a great video series on how to play DnD 5e as well as how to DM.
• Pick up the DnD Starter Set if you can, should be able to find it for about $15. It comes with the Lost Mines of Phandelver story module, and a printout of the basic rules. I have been running this story module as a DM with my group for over a year now. Running A pre-made story module is a great way to ease into being a DM in my opinion, and you can always modify the story however you want as you go, no need to literally stick to it line for line.
• I would also be remiss not to mention Matt Colville's Running the Game series.

Running combat in "theater of the mind" is free, but personally I really like tactical grid based combat. If you find yourself with some $ in the future, a great way to run minimal combat in person is with

• Pathfinder Flip Mats: Basic Terrain
• A set of colored dry erase markers
• A set of 7/8" colored poker chips

Best of luck to you, let us know how it goes!

If you're considering buying into D&D Beyond, I would really recommend purchasing the physical Essentials Kit:

https://dnd.wizards.com/products/tabletop-games/rpg-products/essentials-kit

You'll get the physical products plus a 50% off coupon for the Player's Handbook on D&D Beyond. Finally, you also get access to the D&D Beyond Essentials Kit Bundle for free via an included coupon.

https://www.dndbeyond.com/marketplace/bundle/essentials-kit-bundle

First off, welcome to the DM’s chair!

I would just get the PHB to start, on DDB it’s totally affordable at $30 (USD), and it will give you and your players the most options for the lowest price. If you decide that its for you, you can get more later. Read chapters 9 and 10 twice. 

Have fun. As long as everyone at the table is having fun, including you, you’re doing it right. 

Ask questions. That’s what we’re here for.

Run a session 0!!

And the absolute best advice I can ever give any new DM is Watch This.