Bitcoins ! The most talked and most debated currency in this decade has gone past $4000 mark. We may see several corrections prior to Bitcoin goes further up most probably. So basically those who invested when the price dropped to $2500 - $1800 odd rate are now enjoying a high scale return on investment. Several factors did made the price drop to $1800 after it almost reached $3000. Mainly it was due to uncertainty fueled by segwit2 and also due to certain government activities worldwide. The main reason for the recent bullish beheviour of bitcoin crypto currency can be seen due to two main facts. One is the finalization of Segwit2 with the break away group Bitcoin Cash and popping up of many alt crypto currencies ( ICO ) worldwide. So in order to fund most of the ICO projects, the traders do need BTC. Therefore traders entering in to Bitcoin world has risen ( So this is why you need to be bit cautious and you need to expect small to large scale corrections time to time. Just hold on to the bitcoins you bought, don't sell it at such price adjustments ! ).
So in general best thing is to buy and keep as much bitcoins as possible as a long time investment when prices drops time to time. If you plan to just buy and sell when price starts to go against you, then please stay away from Bitcoins or any alt coins mate ! This is only for the guys who likes to take a long term approach ! So if you are interested in buying bitcoins then you can read "How to buy bitcoins using Credit/Debit Card, Neteller, Paypal or Skrill online" article.