if we only have small money, then we can buy bitcoin with small parts too. this is what I like from bitcoin, we don't have to buy 1 bitcoin in directly, we only need to buy what we need. after we buy bitcoin, then we only need to hold for a while and we need to make sure that the price is up then we can decide to sell our bitcoin to gain the profit.
Small parts buying can give you a low profits if you select to hold it for long period and I suggest that if you buy a small portion of bitcoins on these state and try to trade it on trading sites so that your small portion will grow and by the time bitcoins hits another pump then you can earn more money for that doings.