If budget allows, just painting the room will give it an whole new fresh look and kids will see the change too. I would paint it white or off white and if you can, new curtains that will match either bedroom rug or a colour in bedroom rug. The white paint will bring out carpet and bed colours well. Or, add a bigger bedside table for them to share.

Thanks so much guys!! I want new furniture, and curtains. They're furniture is crappy. How about target?

furniture can be/get expensive. What I have done in the past is painted old furniture and it looks brand new. You can add an inset piece of bead board in the middle of the headboard to spruce up the old frame. Similar to the picture....

I have found ikea furniture to be much better quality than target actually. Unless you've had a personal experience otherwise I would try ikea. It's great for kids storage, rugs, art on a budget. I do like target for storage bins, home accessories and lamps though.

IKEA has tried to get so much better in recent years... but again there is the low end and the high end in IKEA (which is still reasonable)

The frame to the beds look great so I would just paint them a fun color and paint the walls to freshen things up. I would keep the bed frames the same color though and just personalize the bedding. To go a step further, I would frame the window with simple wood boards, fill the seams with putty and paint them white. So easy and so cost effective.