Groupon offers a $30 Threadless Credit
. That's half off and tied for the best such deal we've seen from Threadless, a purveyor of "unusual" T-shirts. The voucher is valid from July 4 until October 10. It's not valid on sale items. Shipping starts at $4.99
. (It's not included in the credit.) Deal ends July 2 at 3 am ET.