You can start buying, but I don't think the bottom is reached yet. $3.000 dollar is in sight, a psychological barrier and may cause another drop.
I have set up buy orders at $ 2500 and will also buy ETH and LTC with it.
In my opinion it's better to hold your money till 30 Sept, until that day we only need to watch and learn the bitcoin's graphic. Then after 30 Sept it's time to decide buy Bitcoin or buy altcoin