Sending students for conference presentation with no additional funding Me with my two students got a paper accepted at a high-ranked CS conference. We have to register for the conference along with travel for presentation and other formalities.

I instructed my students to finish the formalities such as register, book for air tickets etc.

However, I find that I don't have fund presently to book for air tickets and do the registration. Although, they agreed for the process, I am not feeling relaxed on this situation.

Did I do justice for this situation?

However, I told them that we can look for some travel grants after the tickets are booked.
It may be possible to make some of the conference cheaper overall. To give an example some IEEE conferences registration fees are very expensive, this can't be avoided. The last one I attended was also in an expensive hotel. It may be possible to get other accommodation further away and travel in. They may ask for student helpers as well, which could add extra discounts. Early booking may give early bird registration fees as well. The flights, which I assume are required equally might be cheaper in advance.