While getting an original artwork has it advantages, there can always be some good reasons to get the mass-produced version:

When you’re decorating on a budget: one or two original artworks can add a lot of character to a room, but you might have a lot of empty wall space you need to fill. For these areas, a tasteful poster or print could do wonders.
If there is a famous piece of art that inspires you: A poster reproduction of a Gustav Klimt painting may inspire you whenever you view it, and this is a valuable trait for a piece of artwork to have.
For temporary spaces, like cubicles or dorm rooms: Sometimes, the effort of finding the right piece and hanging it can be too much, especially if you don’t plan on spending much time in that space. Posters and decorative art are great for these settings.
For any messy area that would be too hazardous to place original works: Original artwork can be fragile. If there is a room in your home that experiences very high humidity, or has dirtier air (dust accumulation or tobacco smoke), you can decorate these areas with less expensive, printed artwork.
For children’s bedrooms: Children are constantly growing up and changing their preferences. A less-expensive print, poster, or decorative piece can add character to their room without breaking the bank every time your child decides to ‘remake’ themselves.

Here are a couple of online websites you can take a look at, if you rather not get something from IKEA, Amazon or Target:
Society 6
Saatchi Art