Does Best Buy have a 27 inch iMac to sell?'

According to their website they do (if you're looking for the 27" 8GB, 1TB version). I would just call them to make sure.

Check online

one thing to remember to ask if you open the box May u return.My daughter a fan for me and I open the box put it together it didn't work She tried to return it and the kid said That you can't return it You opened the box