Protective Flip Case for Samsung S3 i9300 shipped for $14.95 @ Gadgets4Geeks
I first spotted this deal when pricing up Unique Mobiles promo for the same cover which had a "50% off coupon" applicable to it. But for the same pebble coloured cover, it worked out to $20.25 including shipping. The only thing with Gadget4Geeks is they're limited to these colours: black, white, marble, pebble and sapphire. Unique Mobiles have a wider range with 10 different colours available.
By the looks of it, other retailers are charging anywhere from $29 to $40 with delivery for the exact same covers.