The T-shirt rack at Value Village thrift store in Riverdale, Md., offers 50 feet of cheap sartorial statements on every institution: everlasting love (“Katie & Danny,” $1.95), national pride (“Famous Places in Israel,” $1.25), and municipal delusion (“D.C. Has Got It Together,” 95 cents). On a recent tiptoe through the T’s, though, there was one standout in terms of condition, color, and cost: a like-new red XXL proclaiming, “Re- Elect Mayor Sharon Pratt Kelly 1994.” Perhaps at some future political memorabilia convention, this beauty might bring big bucks, but at $2.95, it seemed a trifle pricey.