I want to give my friend undertale on steam.

So I have a Steam and have received Undertale from a friend for £6.99 as a gift. One of my friends would like to play it and honestly I would love to give a copy to them. One day I received a notification from the exact same friend who gifted me Gmod and they claimed that they didn't buy a copy, but rather just clicked "Send As Gift" and it was just passed over without paying. I asked how, and they guided me through it, but it just asked me how I wanted to pay for it and using what card details.

I figured that I could somehow give Undertale to my friend for free as they seemed to be able to do the same for me with Gmod. I have tried copying the .exe and sending it to them, but that also requires Steam to open and since their Steam says that they haven't technically payed, it won't let them play it. I would like to know if it is possible to send a friend an already payed for game on Steam or if it's possible to send them Undertale without opening Steam so they are able to play it.
Asked Dec 19, 2015

TIP: If it's not your answer to this question, please click "Leave a Comment" button under the question to communicate with the question owner.