Soda stream vs Homemade carbonizer for making sparkling water

Hi

I am getting tired of the huge amount of soda bottle i have to recycle all the time...

So I consider making my own carbonizer or buying a soda stream mashine..

Can anybody tell:

Is the soda stream maker available with 1.5/2 L bottles ?
How many bottles can you make from 1 CO2 tank in a soda stream ?
Price/L of sparkling water made with  a soda stream ?
Can you refill the soda stream co2 tank or do you need to swap it with a new one like in Europe ?

Making a homemade carbonizer will cost a little more than the soda stream machine and probably
make the sparkling water cheaper...

But I just wonder if  it is worth the trouble....

Is it ?