She has enough money to do Hajj but she does not have a mahram

It is not
permissible for a woman to travel without a mahram, even if she is
travelling for the obligatory Hajj or obligatory ‘Umrah, according to the
more  correct of the two scholarly opinions, because of the report narrated
by al-Bukhaari (1729) and Muslim (2391) from Ibn ‘Abbaas (may Allaah be
pleased with him) who said: The Prophet (peace and blessings of Allaah
be upon him) said: “No woman should travel except with a mahram, and no man
should enter upon her unless there is a mahram with her.” A man said: O
Messenger of Allaah, I want to go out on such and such a campaign, and my
wife wants to go for Hajj.” He said: “Do Hajj with her.” 

Because of
this hadeeth and others which indicate that it is haraam for a woman to
travel without a mahram, a number of scholars are of the view that the
presence of a mahram is one of the conditions of Hajj being obligatory for a
woman. So if you cannot find a mahram to travel with you, Hajj is not
obligatory for you, and you are excused, but will be rewarded for your
intention in sha Allaah. 

Imam Ahmad
(may Allaah have mercy on him) was asked about a woman who was well off but
did not have a mahram – is Hajj obligatory for her? He said: No. 

Al-Mughni
(3/97). 

The Standing
Committee was also asked (11/95): I have a problem for which I want to find
a solution from Allaah, who is Merciful towards His slaves. It has to do
with my performing the obligation of Hajj. I am a woman in my fifties and
for two years I have wanted to travel to perform the obligatory Hajj. What
is preventing me from travelling is that I do not have a mahram who can
travel with me. My husband has no concerns except work and worldly matters,
and he does not intend to travel for Hajj, unless it is arranged for free by
the company for which he works. That will not happen until his turn comes,
and I am afraid that I may die before I perform this duty. I have enough
money to pay for provisions and the journey. To sum up: all my mahrams are
unable to travel with me because of their work.  

They
replied: 

If the
situation is as described, and neither your husband nor any of your mahrams
is able to travel with you so that you can perform the obligatory Hajj, then
you are not obliged to do it so long as this situation persists, because the
presence of your husband or mahram for the journey to Hajj is one of the
conditions of it being obligatory for you. It is haraam for you to travel
for Hajj or any other purpose without a mahram, even with your brother’s
wife and a group of women, according to the more correct of the two
scholarly views, because the Prophet (peace and blessings of Allaah be
upon him) said: “No woman should travel except with a mahram.” Saheeh –
agreed upon. Strive to do righteous deeds which do not require you to
travel, and be patient, in the hope that Allaah will make things easy for
you and grant you the means of travelling with your husband or a mahram. End
quote. 

Fataawa
al-Lajnah al-Daa’imah (11/95) 

We ask Allaah to guide us and you. 

And Allaah knows best.