I notice a lot of reviewers buy the sample piece


When I read Absolute Sound or Stereophile I notice quite a few reviewers will buy the sample gear. Do they get the piece at dealer cost or even below that? I wonder if they have to keep it for a period of time before they can resell it?

taters
It's an endorsement but not the ultimate unless the list price is paid.  

Cmon this is America where money always speaks loudest. .  Could reviewers on the take possibly surprise anyone. 
Arthur Salvatore has a lot to say on this subject on his Reference Components website.
reviewers also tend to only review equipment they have heard and liked. no one wants to listen for a few months to gear they do not like.
out of curiosity I did a quick random check, and noticed only a small percentage buying the reviewed equipment...

read between the lines...

when the reviewers mentioned they received the component from previous reviewer or it has been burned in already or whatever tell-tale signs, all kinds of endorsement, "highly recommended", their purchases are simply their marketing gimmick. Reviewers whom can honestly compare between similar gears in a controlled audio setting, highlighting strengths & weaknesses between components are rare these days.