Musicol is probably the cheapest option. United had a 100 LP "spring/summer" deal on their website that lasted almost the entire year. It's not up there now, but it was 100 LPs on black 140g vinyl w/black/white labels, 5 test pressings, plain white sleeves (w/center hole), including all plating, mastering, shipping, etc. for $699. Honestly that would have been your best bet. If you were to place a similar order now, it'd probably be like $900-1000.