Currently the price of Ethereum is very low, only $ 150, this is a good opportunity for us to buy more ETH. I guess the next spring, the price of ETH will be higher than $ 900
I don't think the price is low at all. It only seems low because people compare the current price to the all time high of $1.3k, but that high was solely the result of ICO buyers who didn't care about what price they bought at.
If you wanted to buy $10k worth of an ICO, it makes no difference if you buy Ethereum at $50 or at $1k, because these people don't hold these coins for longer than at most 30-60 minutes. That's what drove Ethereum to that high.