In my opinion, you can never go wrong when purchasing higher-end brushes! Sure, they may be a little out of your price range, but when it comes to good quality and a long lifetime, everyone should splurge! One really good brand I love is Sigma , they have amazing brushes that last a long time! You can buy brushes in full sets, or individually! A good makeup brush can do wonders when applying makeup, I know from experience that using better brushes makes my makeup look better! I also want to add that you can find really good brushes for a lower price at Crown Brush . Also some of the E.L.F. brushes you can find at Target or online at their website are very good and affordable, they are not as high quality but some of their brushes work great!
This is one of my favorite sets! The Make Me Blush Essential Kit!
Tip: Clean your brushes as much as possible, dirty brushes spread germs around that are stuck on the brush! When washing brushes keep water and soap just on the hair of the brush, getting it on the handle will soften the glue used to hold it together and will loosen the brush which sometimes makes it harder to use!