That is one of the advantages of Bitcoin over other types of investment like Gold, Real Estate etc. With as little as $5 or less, you can own a piece of bitcoin. And if you decide to be on an investment streak with the little $5 weekly, by the end of one circle, ie 4yrs, you could own a good fraction of bitcoin. Maybe the best thing to do is to give it a trial and see how it goes. Don't go all in, just go with the amount of money you can afford to lose.