It seems like investing your money each month is a good idea if things take off.
Maybe look at it from another angle as well, that is tell as many people as you can, I think that if more people get on it and use it that will increase the value far beyond just putting money into it. You will be investing in yourself and the community. So invest time in it, support others and help each other grow.
RE: What is the best way to invest in Steem for the long term?