There are some very cheap presing plants out there. I've pressed some 7"s in the past (the original music of the band I was in at the time, NOT BOOTLEGS!) and pressing 200 or 300 usually costs about £1.75 per copy (including postage, labels, paper sleeves and everything). So that's about £525 to press 300 copies (minimum order is ususally 100 copies). You then manage to sell 200 of them for £10 each, that's £2000 and a profit of about £1500, if you sell all 300 copies you make a profit of £2500. And these people don't just press up ONE title, they probably have 50 different titles "running" at the same time. That's a profit of 50 x £2500 (£125000) if you sell 300 copies of all the titles.