First, are you registered to collect and remit sales taxes?
The revenooers get grouchy if you are not.
And are you using the Advanced Sell Your Item Form or the single page simplified form eBay shows newbie buyers?
BTW-- are you aware that Paypal will Hold your customers' cleared payments for 21 days against your good performance? This is a Buyer Protection policy and nothing personal.
However, you can print out PP shipping labels from the cleared payment, and on some services there is a 5% to 18% discount from PO counter prices for doing so. So there's that.