Posting your own sales in someone else's sales thread is off-topic (and thus not allowed). It's also extremely rude in my opinion.
I would agree if wakka were still here but since he has not been online for a while and isn't responding to messages it's better that someone steps up and offers services than leaving people unanswered
I agree with Mitchełł, as the fact that Wakka is not online or very active does not change the fact that you are posting your own sales in someone else's sales topic. Yes, I think this is rude too.
You're right in the sense that he is not online or responding to messages. However, I think people will find this out themselves too: if they still want to buy a specific game (or something), they can look for other sellers on this forum on their own.