A Future contract is an entirely different animal. With a future contract there is no payment upfront either way, it is an outright buy per a date in the future, at a price agreed upon at the outset. Both parties are obliged to fulfill the contract at the end of the agreed upon period.
Hmmm, I'm not a finance guy, so I don't know; but this doesn't sound right.
I thought that futures worked so that you bought something now that the seller doesn't have yet.
The classic example is the farmer. The farmer can sell (say) wheat at $100 a kilo in September; but to do so he needs to spend money now to buy seeds, labour and tools. If he doesn't have that money, he will get $0. A futures buyer offers $90 per kilo right now; giving the farmer the capital he needs to produce the wheat.
i.e. the money changes hands now; the product changes hands in the future.
Have I misunderstood?