Usually they recommend you to diversify your investment, so you avoid losses.
But as a real approach, having $1.5k, would you invest in how many cryptocurrencies ?
What if I invest little by little, only in Bitcoin, would that work as well ?
Work or not an investment depends on your analysis and strategy, you want to invest a lot at the same time or investment from little by little if you do not have knowledge on the investment then it is not work. $1.5k I think it's not enough if you invest only in bitcoin, in my opinion it actually makes your profits smaller because the value of bitcoin and bitcoin fluctuations is relatively slow from altcoin, but if you choose a small risk then bitcoin is the best thing.