The price of windshield wiper refills vary according to what you buy. You can buy just the refill blades, which is just the rubber and a piece of plastic around it to add stiffness. Or you can buy a whole wiper arm refill that makes wiper replacement literally a snap. Bosch, Rain-X, Anco and Trico make the most popular and widely available wiper refills available, with prices ranging from the $6 range up to $20 for standard refills. Double bladed refills and “advanced technology designs” will cost as much as an extra $10. Every parts chain also offers a “house discounted” brand. These will normally be a few dollars cheaper.
For more info, see DIY Car Maintenance Servic: What to Do Yourself