I met my wife on the internet, but proposed to her in The Association For Retarded Citizens of Tempe Thrift Store with a $.25 thrift bought ring.
It was one of those "free" diamond rings they give you for some mail away or time share deal. The ring was of course adjustable, had the thinnest layer of one karat gold that it could possibly have, and the diamond was almost microscopic. My fiancee wore it from then on, for about a year until the diamond fell out.
I replaced the ring with my grandmother's engagement ring provided by Mom.
We've been married for 3 years and owe our engagment to a thrift shop.