Just a mental exercise:
$ 55 - 1 tank of gas (@ 625km / tank)
$225 - Ferry to Argentia (car)
$112 - Ferry to Argentia (me)
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$342 (x 2 for Return) = $682
So you can drive/ride there for $150 less, though it takes a full day each way. Becomes even more cost effective if you car-pool...
$ 55 - 1 tank of gas (@ 625km / tank)
$225 - Ferry to Argentia (car)
$112 - Ferry to Argentia (me)
$112 - Ferry to Argentia (passenger)
$112 - Ferry to Argentia (passenger)
$112 - Ferry to Argentia (passenger)
-----
$728 (x 2 for Return) = $1456
This saves you $1,884 on a round trip for four and comes to $364 per person (vs $835).
Though you might wanna pay an upgrade for a berth on the 16-hour ferry ride... but truth-be-told... the ferry is a LOT more comfortable.