Choose from two options for this Groupon: $15 for $30 worth of bargain books or $25 for $50 worth of bargain books from BookCloseOuts.com.  So you’re getting half-off half-off? This retailer’s constantly updated stock of bargain books includes new arrivals, kids’ books and mildly scratched and dented titles at a reduced price. Shipping isn’t included, but I checked and they use standard USPS rates for media mail ($3.99 for one or two items…