ASUS' Transformer Pad 300 should arrive in the US on April 22 if Amazon's site is correct, where it has been listed to be available for $489.99. For those in Europe, it will arrive mid-May for EUR 400 (roughly $525).
The ASUS Transformer Pad 300 (TF300) sports a 10.1-inch screen with a 1280x800 screen resolution, 1.2GHz Tegra 3 processor, 1GB of RAM, 32GB of internal storage and software-wise rocks Android 4.0 Ice Cream Sandwich. Compared to the Transformer Prime's specs of a 1.3GHz processor, it's not too far behind. It is however thicker and heavier: 0.39-inch thick and 1.4lbs in weight, compared to the Prime's 0.33-inch and 1.29lbs in weight.
There's no word on the keyboard dock yet, but it should be around EUR 149 (or $195) when it hits.