The easiest way to update a kids bedroom, other than paint, is with wall decals. Kids have so many favorite characters, you can bring their room to life with them all. In this case the decals are so cheap, buy them all and change them out ever so often for a change.
We found these Character Wall Decals for $3 at our local Walmart. But Doing some research at other stores near me we found them available for as low as ONLY $1 (Reg $17.99). Check your store to see what kind of deal you can find. YMMV
Ryan’s World Wall Decal SKU#201918492 – Disney Princess Belle Wall Decal SKU#702394020 – Baby