Don't know what to buy when you are first starting off of your photographer journey?
There are so many different choices depending on what you want to shoot.
When you are starting out, always make sure that you get a 35mm 1.8 or a 50mm 1.8 for general purpose or portrait photography since they are fast, fairly inexpensive and great in low-light situations.
If you want to shoot architecture, real estate, buildings or cityscapes, then getting a wide-angle lens is going to be your best choice.
They tend to bloat or distort the image, so it's a NO NO to use these type of lenses for a portrait shoot or headshot.
Wide Angle Lens for Nikon
Wide Angle Lens Sigma
Wide Angle Canon Lens
If you want a great little walk-around lens for general-purpose photography, street photography or even vacations, this is my favorite angle on a crop sensor camera. Using this type of lens will act as a 50mm on your Canon Rebel or Nikon 3200
35mm Nikon lens
Canon 35 mm lens
If you are getting into portrait photography, then using a nifty fifty _the 50mm) or a 85 mm would be a great way to capture images and faces that aren't bloated or distorted.
50 mm Nikon lens
50 mm canon lens
85mm lens canon
85 mm Nikon lens
If you want to get into sports, event or nature photography, then getting a telephoto lens will be your best bet.
When you get into weddings and more expensive venues, then making sure that you get lenses that are f3 or less so that you don't have to rely on flash so much. Cheaper lenses are going to be f3.5 or above since it's really expensive to get lenses that are f1.8, f2 or lower.
Canon Telephoto Lens