Based on the limited PR package, most labels base their lowest sales around 700 unless its a big name involved.

1/4 page B&W in Classic Rock Mag = £850+
At £3 cost price per album, that's 283 sales just to cover that single advert sales to. Cds sell wholesale between £4.00-5.50, so do the maths on the margins. That's only one promo outlet.