What price range should I expect for Storj and will it be permanent too?
Prices for storing files on the Storj network will be dictated by the market (supply vs demand). Most likely they will be waaay lower than Dropbox rates.
Keep in mind that price for space is on Storj is one thing and the value of SJCX is another. Both will be controlled by the market. the valuation of SJCX will be factor into the cost of space on the Storj network.