I have never used Amazon or Ebay before.

I started shopping and saw some posters for $2-$3 and started adding to my cart. Then I saw some for 1-3 cents! Is it me or does this not make any sense??

Maybe someone can help me understand Amazon better, and if it's just too good to be true? I mean even with the shopping costs, i'm still doing a lot of saving.

Thanks in advance :)