Tell us more about yourself and the kind of riding you'll be doing and the conditions in your part of the world. How much do you weigh and will you jump the bike or be hitting rocks and stuff at speed? Do you want to weave around tight singletrack or descend fast fireroads or both? How muddy are the riding conditons in your area? So on and so forth.
Make your decision based on fit, suitability for the type of riding that you will be doing, reputation of the bike brand and reputation of the shop. Fit is most important thing. Don't buy a bike that is too small because you think it looks cool with a long seatpost jacked up high (common problem).
Take a bathroom scale with you and weigh the bikes yourself and take notes. Test ride the bikes. Take a tape measure and measure saddle tip to handlebar and handlebar width and take notes. How far away and how far apart your hands are makes a lot of difference because that is your position. If you're new to the sport don't make the mistake of getting something that sits you too upright. You need to be bent over some to use your quads and gluts correctly. You'll get used to it in time.
Make the bike shop a big part of your decision. Choose a shop that will take care of you after the sale. That doesn't mean free parts to replace ones you trashed or wore out. But you should expect free tuneups for awhile and they should take care of you if you do have legimate warranty claims. A bike shop that sponsers local racers and organizes local rides and shares information about good places to ride would score points with me.
And have a good time. There are so many good hardtails to pick from in your price range that the hardest part will be making up your mind 🙂