I paid sooooo much for Eh, Eh. Like 50 dollars or so I think? I got that in 2010 I think? But it was already fairly rare then because it was only released in select places.
You and I and Marry The Night I got as Christmas gifts, but yeah they were fairly cheap when they came out.
I actually only got the Applause single recently, from Amazon pretty cheap. It's actually still available on there. I thought all copies would have been slimline but I guess it depends on the place/region. I wish the other Artpop singles were released physically too.