Is it profitable? I bought one from Amazon and with default settings, about 10Gh/s I earned 0.00000716BTC the 1st day. So in about 5 years I will earn 0.01BTC (without calculating power cost) which is way too low.. If I did not do any mistake or misunderstood something it seems there is no point to use it.
Even if I increase frequency eg with 25Gh/s I will earn 0.01BTC in 2 years...
Please tell me if I am wrong.
Small USB stick miners, like this one, are more for getting started in the bitcoin mining game. They are mostly a learning tool, but also a way for you to join the community. That said, the miners do contribute to the distributed nature of the bitcoin network. Unless you are solo mining and find a block, which is not impossible, just highly improbable, they will not return your "investment."