Ohio customers pay 8% sales tax. EBay handles collection and remittance of taxes from an increasing number of other states. I combine shipping on won items but please aggregate things and pay in a single payment to save multiple paypal payments.
$5 domestic/$15 international tracked shipping for items over $50; $1 domestic $2 international for items ending under $50 (I will reinvoice if you don't want tracking). I will try to reinvoice items under $50 to save you postage if you don't want to pay for tracked). I use at least one current stamp on virtually all outgoing mail.