If you can't afford original art, an art print is a great compromise. But please, upgrade from the paper posters you had in high school. You can find beautiful Gicleé art to hang on those blank walls in many formats; on canvas or framed art paper. But be forewarned - not all art prints are Gicleé and not all Gicleé's are limited editions.
If you can afford it, try to buy signed limited edition prints. This means the artist numbers and signs each print and after the series is finished, that is the end of those sales. There is one original, and those prints. Finis. Lucky you if you bought one!
Find out more about the process and the differences here - and if you have more questions - ask me!