Shoppers say "it does not squeeze the tummy or upper arms"Credit: Alan Chapman/Dave Benett/Getty Images for Apple TV / AmazonIt’s not every day you can dress like an A-lister for less than $30.We found a top that looks so similar to one Jennifer Garner wore recently on sale for just $27 at Amazon. In a sweet Instagram celebrating two of her favorite teachers from childhood, the actress had on an airy black polka-dot blouse. That classic pattern …