Check iResq ($99 to $145 depending on model) or your nearest Apple store ($199 to $379). For the iPhone 6 Apple is significantly cheaper than any other vendor I've found, and they do it while you wait. But it seems the iPad is a different story.
In rereading your post I may have misunderstood. Do you plan on buying a screen and replacing it yourself? If so I have no recommendations, never did that.