Standard bird cages are pretty small, usually to small for gliders. My cage which is comfortable for 2 gliders is 36 inches high x 22 inches deep x 33 inches wide.
You probably need to upgrade her cage size especially if she is doing repetitive circles, those are stress circles and usually happens when a single glider is lonely and bored. She really needs a bigger cage and a cage mate.
In the meantime you also want to really should look over the cage she is currently in and check for any rust spots or erosion. Gliders tend to slide down the bars and erosion/rust can do some damage to their feet.
Make sure the wheel is glider safe, hamster/rodent wheels or wheels with a bar through them are not safe for gliders. Wodent wheels are also not safe and have been the cause of broken tails and even glider deaths.
These are glider safe
http://www.mygliderwheelsandmore.com/shop-for-wheels.html
And so are stealth wheels I think there is another one but I can't remember the name of it.
A wheel is pretty important for them and may help alleviate the over grooming, but it may not completely resolve the fact that she is lonely and needs a cage mate.
As for toys there is sooo much you can do for very little cash. There are things you may already have around the house that are glider safe. Drinking straws ( you can also put yogurt or applesauce or honey in the ends of the straws for treats just make sure to toss them out in the morning )
braided fleece vines for her to Undo, a clean cool whip or sour cream container with a 2 inch hole cut in the lid or side of the container, Pompom's for a ball pit, pingpong balls, plastic easter eggs for foraging treats, tooth brush protector for foraging treats, cat toys that are cat nip free cat nip is toxic to gliders, crafting feathers we got a feather boa at the dollar store mine just love!! plastic caps from soda bottles or milk jugs, the big plastic ring from mayonnaise containers are a favorite here lol.
* If using plastic rings from other types of bottles or jars make sure the ring is big enough it won't get stuck on their neck or small enough their head won't fit through it*.
Then of course there are toddler toys, plastic tractors and cars that they can fit in. Make sure any holes or hiding spots are big enough they won't get stuck.
Try to avoid wooden toys and painted wooden toys, wood absorbs urine and is impossible to keep clean, paint or stain can run off even bird toys when they get wet. Most people also avoid toys with metal chains or hardware, some metal has a reaction to glider pee.
I have a picture folder of all the toys I've made, mostly from stuff I already had around the house if you want to look there for ideas please feel free.