Quoting Fatwa: 90273 that women can only travel with "Mahram", what if you can't afford to pay for two or no Mahram available at that moment and nevertheless its the only time you managed to save money for her. And also is the baby considered as Mahram?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

We have already clarified in the mentioned Fatwa the prohibition of a woman traveling without being accompanied by a Mahram (unmarriageable man). The ruling includes the situations if she does not have a Mahram or she cannot afford his expenses or the like.  So, she is not allowed to travel unless there is dire necessity such as her being in an unsecured place where she fears on herself, or willing to migrate from a non-Muslim country to a Muslim country. Allaah Says (what means):  {He has explained in detail to you what He has forbidden you, excepting that to which you are compelled.}[Quran 6:119]

As regards whether or not the baby is considered a Mahram, then the Mahram that is required when travelling is a mature and sane male.

Ibn Qudaamah said: "It is stipulated that a Mahram should be a mature and sane male. Imaam Ahmad was asked: "Can a child be a Mahram?", and he replied: "No, until he reaches puberty, since he cannot take care of himself, how can he travel with a woman? The purpose of Mahram is to protect the woman, which is not possible except by a mature and sane male." [End of quote]

Also, the Hanafi and Shaafi'i Schools of jurisprudence clearly mentioned that a child and an insane person are not considered as Mahram. So, a child is not sufficient as a Mahram in this matter since he cannot protect a woman.

Therefore, it becomes clear from the above details that a baby cannot be a Mahram for traveling.

Allaah Knows best.