Aaaaand the question goes to whom?
If me, then, it was acquired by hard work and guts, clever rearrangeing of pocket money, and excluding everything else like getting out for a drink with other dudes, because I always spent my money on legos. Sources were toyshops(surprise, surprise!), and bricklink sellers. Also shameless lootings and gratuitous donations from some pal's collections, and blending it with my existing amount of bricks. Also, I began when fantasy era hit the shelves, so it was an armybuilder's paradise.
Since I collect transformers, I can gain some extra money by selling some of my unwanted figures. Like, sometimes in june, I'm expecting a 40$ (in my currency) income, which would come just in time, as I'm planning to raise a new squad of orks.
I can be quite passionate when it comes to collecting.