Can iphone 4s and 5 be unlocked without taking any contract with the carrier itself?

Can iphone 4s and 5 be unlocked without taking any contract with the carrier itself?

Yes. You can purchase one from Apple already unlocked.

YES IT CAN.

Yes there are many services out there such as iphoneunlockedcheap.com who can IMEI unlock iPhones. It depends on which carrier it is locked to though. Some unlocks are expensive, whereas some (like ATT) are very cheap.