I just enquired on your behalf..its $16 for A1, non-student rate.
i gave an estimate of 5 pieces to be printed.
one thing to note thought, you probably can bargain (within reasonable limits of course). I think you can take the $12 to be the lowest price they will go.
I think you can remind them that yor friend from NUS architecture printed $12 for student rate if they deny it.
They use HP large format inkjet printers, not too sure which model..high end ones.
paper used is sysnthetic poster paper..the kind.which you can't tear.
The price includes lamination, choice of matt or gloss.