This is what Ive just started to do, since finding the crypto world in late August. I sold some altcoin I was given and started out with $500 in BTC, which grew a little from the end of September. HODLing the rest of my altcoin (not worth much at the moment anyway, may never be), and my plan is to ACH what little fiat my budget allows right now from my bank to my coinbase account, where Ill buy BTC at the current market price. Ive now got 73% in BTC, 17% in LTC and 10% in OMG (not even counting the odd altcoin Ive got). I should maybe exchange for a little more LTC and make it 70/20/10, IDK. Every two weeks Ill transfer about fifty bucks in and buy more. Maybe my altcoin will moon at some point. Any little bit my budget allows is going to BTC right now, so that I can get to that 1 full BTC! Once Im above 1 BTC, Ill take the advice you hopefully get here and grow my own portfolio, too!