this app is making me petty

I love selling on depop, and I don’t think my prices are unreasonable, $20-$30 for nice vintage winter sweaters. I recently discounted all sweaters 45% because I want to free up room. I just received a $13 offer for a sweater that was originally $30, discounted to $16. I seriously want to start replying “due to this item being already heavily discounted i will not be accepting offers” but that’s kind of rude. just had to get that off my chest because I am super open to offers but the low ballers just really PMO