The only other way to stop a bunion from growing out other than bunion surgery is to wear some foot supports in your shoes or look online or go to your local drug store and look for gel filled pads or moleskin pads to help your feet and bunions.
You can also help stop a bunion from growing and progression by using other shoes inserts which help to position your foot correctly.
That can help manage the bunion growth although the only sure way of correcting a bunion and stopping a bunion from growing at all is to get bunion surgery performed on your foot.
Check with your insurance company because sometimes a health insurance company will cover the cost of the bunion surgery.