Futures contracts are not the same as call options.
I will try to explain the difference.

The buyer of a call option buys the right to enter into a transaction at the agreed upon exercise-price during the contract period (or only at the end of the period, depending on the type of contract). The buyer of a call option needs to pay the option price up front, but is not obliged to exercise his right. Obviously he would only do so if the actual price goes above the exercise price, and he would make money only if the price rises to exercise-price plus the amount paid for the option.
The pricing of these options depends mainly on calculations of the risk/chance that the exercise price will be hit.

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.
For the pricing of these future contracts in the real world, at least for financial values, the only determining factor is the interest rate for the contract period.

Obviously, without a trusted exchange that carries such products and solves the trust issue, neither options nor futures are viable instruments for the bitcoin market.