If they are just cheap sunglasses, somewhere near the registers of places like K-Mart, Wal-Mart, and pharmacy stores you can usually find the little kits with a variety of screws and a tiny little screwdriver.
If you have lost a screw, you can use the wire in a bread tie to thread through the hole and hold the glasses in place until you can get them repaired. Strip the paper from the wire on the bread tie.
Hi, I work for an Optometrist and the best advice I can give is to take your glasses to a practice- preferably the one you got them at. If it's been under 2 years there is usually a manufacturer warranty against defect. Unfortunately, if the spring is broken it can't be fixed. But, they may be able to find a spare part from another broken frame to 'jerry rig' yours with. Good luck!
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