Companies can technically buy a quantum computer right now, but it's not really the same as a general-purpose computer. Even if you don't question whether or not it is quantum computing, it really amounts to specialized hardware. However, IBM hopes to change all that: it's planning to build the first commercially-oriented universal quantum computer. The plan is to build a system with roughly 50 quantum bits (the Quantum Experience started with 5 and now simulates 20) within the next few years. That may not sound like much, but 50 qubits could be more powerful than the best supercomputers when handling some calculations -- tasks that were impractical before would suddenly be within reach.