Obviously you need a few different styles in order to get more customers (New and Old). In case you didn't know, a lot of people prefer the new ones over the old ones (I personally don't, but I'm not wearing them). You can also get new ones for cheaper, which means more profit for me.
Onto the critique of your constructive criticism. I do not talk like that, because I didn't write "cop these", It was my friend. I admit that he is pretty illiterate and there's nothing I can do about that. Also, "lemme get this one nigga" was not me that typed that either because that was a customer asking to buy a hat, which could of easily been discovered by you if you would have read the name of the poster. And "prices negotiable" is perfectly fine to use in this situation. So hop off the sack