Ok cool, anyways. It's usually better without the comma, as to show whoever you're talking to clearly does not care about what you just said and would like to move on or tell you about why they're angry with you, or the weird dream they had last night. If someone says this to you, they might be a bit ignorant or just in a rush.
Person 1: Hey did you hear about {this or that}?!
Person 2: Yeah whatever
Person 1: Isn't it crazy?!
Person 2: Yeah ok cool anyways