M.D.
Here are a few ideas from what I did with my daughters nursery.
Fairy Wings - (about $3.50 Hobby Lobby) it will be tricky but use the strings in the back to nail them to the wall. You will have to wrap the strings around a few times and play with it to get them to stay up. They can hang a little so they are not flat on the wall. Get a few pairs of them and put them all over her walls where she can't reach.
Princess Wands - ($1.47 Hobby Lobby) grab a tall plastic vase or other pretty container and put about 5 or 6 wands in it so they look like a bouquet of wands.
Tiaras - (about $2 for 12 at Hobby Lobby) Purchase a pack of 12 from Hobby Lobby and embellish them on the front with jewels or whatever you want. If there is a shelf in her room...or if you want to buy a shelf, rearrange the tiaras on the shelf so they are part of the decor. Have her help you design them so she has a part in this too.
Tutus - I think Hobby Lobby has these too. If she has a little stool in her room you can use the tutu to put over the stool so it hangs down as if the stool is wearing the tutu. Very cute. Or put the tutu over the lamp shade! Just make sure it can't touch the light bulb or anything and make sure she can't take it off.
Bedding - You may be able to find some plain colored bedding somewhere like Anna's Linens that will be more affordable then the decorative kind. Then purchase a set of cute pillow cases and some throw pillows that have decorations on them that will go with the solid color you choose. So you still get all the cute stuff but don't have to pay an arm and leg for all the bedding.
Throw Rug - You can find really cute ones at Wal-Mart and they are about $10 so this should be easy.