BTC has historically jumped pretty fast & people have been unable to time the dips to maximise their gains.BTC is below 10800$& from here to 8500$ you can place orders in two parts of 1/3 rd of the amount each of the total amount you can afford to purchase.It would be better to purchase 1/3rd today and 1/3rd on friday (as stastical data have shown over the years that on these days you get better deals).
As the whole market is correcting Eth,Ltc &Dash are also good coins to buy during corrections but statistically speaking BTC HAS PROVIDED BETTER AND FASTER ROI OVER THE LAST 4 CORRECTIONS OVER A 1 YEAR PERIOD .
This is based on cryptocurrencies that have data to back over a period of time & data usually proves itself 99% of the time .This is my personal opinion & not a financial advice.