I'm assuming TheMightyPikachu was referring to me, so I'll give a brief explanation. I (as well as my gaming group) was in on the ground floor when MtG went into full production (end of Beta & full up into Unlimited), and I invested some $1200 in cards that first year or so. Also, keep in mind that this was before there was a 'card frequency' list, so nobody knew what the rare cards were really. I just had a knack for trading my commons for what turned out to be the most valued rares (power nine, Gauntlet o Might, Forcefield, dual lands, diamond valleys & libraries of alexandria, etc.). From that initial one time investment, MtG has paid for my Ford F250 extended cab - power everything truck, it paid my rent for two years (in '99 & '00), and of course it's paid for all my silly wh40k models, codex books, & all the tid bits on the side. And to complete my Pact, I have a GW retailer contact that sells me everything that I actually pay cash for (from card sales) at 30% off the store's retail price, and their retail price is often less than GW posted retail. I guess the best part is, to me it's like I'm just trading pieces of one game for pieces of another, without losing anything in the long run.
DW