An alternative to 3 that doesn't leave you out of pocket would be to say "this is my mug that I bought, it's nice isn't it - if you like it so much, why don't you give me $X for it (which is how much I paid) and I'll buy another one for me."

I think that's going to make you seem weird, unless you work as like a bond trader or something. Normal people don't do that sort of thing. And the GP's post was about being worried about expending social capital.