You can establish repair cost in your country/region here:
iPad Repair & Service - Apple Support
You can use Apple’s mail-in repair service, or you can arrange repair via the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP):
Genius Bar Reservation and Apple Support Options - Apple
For practical purposes, Apple usually exchange the iPad for a renewed/refurbished iPad of the same model and specification. The cost of the exchange is the same as would otherwise be charged for repair. When exchanged, the replacement iPad is yours to keep.
Whether or not the cost of repair is cost effective can only be determined by you. The repair cost represents a considerable proportion of the cost of a replacement device. Many here would argue that this money would be better spent towards a newer and more capable model.