Where can I get band posters or just posters in General?
You can get band posters or just posters in general at http://bandpostersprintedcheap.com/2009/07/cheap-band-promo-posters-printed-online/ and http://www.allposters.com/gallery.asp?CID=3796483595E84DB695ECC32ADF95F030&startat=/marvel-collection/&AID=84265929&PSTID=1<ID=10&LID=2170&lang=1. You can check them out at your local grocery store and you can order a specific one stomach.
If they have one at your local mall, "Spencers" usually has a good selection of posters - otherwise you can check out their website...http://www.spencersonline.com/
Spencer's or Hot Topic. Both usually have a great selection.
Hmv, or any music store.
You can get band posters in the merchandise section of that band's webpage.