When we travel, we always leave room for bringing back extras. But, if we've been extra spendy at his family's place, we have a spare suitcase we trade back & forth with his brother. When he comes here to visit, he and his wife to all their clothes shopping, because the prices are so much cheaper than in Denmark where they live. When we go there, we load up on foods and candy we can't get here, fabric and thread (I can get a 2000 meter spool of GOOD thread for $4 there), and and anything we got as gifts to us or that we bought for others here. We check 1 less bags going over than we have people going, then have 1 each coming home. It works for us!
Since you didn't expect to do this, I'd say either a carry on from a thrift store or shipping it home is your best bet. Flat rate boxes come in many sizes, with the largest being 12x12x5-1/2. Anything you can stuff in there, ships at that flat rate. Since it's fabric and has to be washed anyway, line the box with a plastic bag & cram away!