At Once
Immediately, Without Delay, Right Away, Right Now
adverb
Doing something both fast and early probably requires you to do it at once or immediately. Whatever it is, be sure to do it without delay.
The reading for this one is strange. The reading for 速 (そく) is what you'd expect (on'yomi), but 早 gets a reading you haven't seen before, meaning you should treat this as an exception. Just think about how you're learning this word at once and without delay so there's no time for any sass (さっ), just kanji learning.
早速買う
to buy right away
早速作る
to make right away
早速やる
to do right away
早速、新しいアプリをダウンロードしました。
I immediately downloaded a new app.
早速のお返事、どうもありがとうございます。
Thank you very much for your prompt reply.
自立してから早速、自分の車を自分のお金で買いました。
Immediately after becoming independent, I bought my own car with my own money.