So, how do we use "甭" in a sentence? For instance,
1) 甭說了。
As "說" here means "talk" or "speak", the whole senence is "say no more".
2) 甭客氣!
"客氣" means being polite. Here the whole meaning is akin to "take it easy".
3) 票掉了就甭進。
If the ticket ("票") is lost ("掉"), you can forget about going in ("進").
As for the last sentence, it is not a direct translation but it does translate the meaning and captures the tone of the original sentence, especially for its second part (the direct translation for "就甭進" should be "don't have to go in".) From the example 1 and 3, the word "甭" is used as an indirect or more polite way to say something - sometimes it's not really about you "don't have to" or it is "not necessary to" do something. The subtext of "you don't have to speak more of it" is you have said enough.
But in today's China, the indirect meaning of "甭" has become as direct as a simple "no". Hence it depends on the context and the tone of the sentence as well.