developing a new alt-coin useful or not? I will try just for educational purposes create my alt-coin. But i have some 
questions before to start.


It's possible create the alt-coin since my ubuntu and maintain this alt-coin since my pc if its always turn on?
My last question, at this moment is possible that this new altcoin get some real price in the market?


Someone can guide me a little or say me if will be useful in something create a new alt-coin? And maybe can get be profitable?
Is it useful?

Probably not for the community, but for you because you learn.


  It's possible create the alt-coin since my ubuntu and maintain this alt-coin since my pc if its always turn on?


There is a difference between creating and running it. But yes, you can create a coin with your Pc.


  My last question, at this moment is possible that this new altcoin get some real price in the market?


If you list it on an exchange and the community believes that it has a value: yes. Otherwise: no.

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If you have only one Pc, you could create an ERC20-token (Ethereum based) and let the blockchain handle everything.