She did not make up the Ramadaan fasts that she owed for nine years
Question

I am a girl who was astray but praise be to Allaah I have been guided. But my question is that I used to fast Ramadaan, but I did not make up the fasts I owed for nine years. There are about 50 days and I cannot fast all of them. I can do half of them and I will give money for the rest of them. Is that permissible? How much should I give?.
Praise be to Allah.Firstly: 
for having guided you and enabled you to do that which He loves. We give glad tidings to you of the forgiveness of Allaah, for the one who repents from sin is like one who has not sinned at all. And whoever turns to Allaah, Allaah will turn to Him. 
Secondly: 
Those who break the fast in Ramadaan for a legitimate shar’i excuse, such as travellers, those who are sick and menstruating women have to make up the days when they did not fast, if they are able to fast. It is not permissible to feed poor people instead when one is able to fast, because Allaah says (interpretation of the meaning): 
“and whoever is ill or on a journey, the same number [of days which one did not observe Sawm (fasts) must be made up] from other days” [al-Baqarah 2:185]
i.e., he must fast the number of days that he missed. 
It was narrated that Mu’aadhah said: I asked ‘Aa’ishah: “Why does the menstruating woman have to make up the fasts and not the prayers?” She said: “That used to happen to us, and we were commanded to make up the fasts but we were not commanded to make up the prayers.” Narrated by Muslim, 335. 
Thirdly: 
It is not obligatory for you to fast them one after the other; you can fast them separately, so fast one day and not the next, or fast a number of consecutive days then do not fast for a number of days, and so on… according what is easiest for you, until Allaah enables you to make up all the days you owe. 
You should start by making up the days missed in Ramadaan of last year, so that the next Ramadan will not start before you have fasted them. 
See question no. 26865, for it is important. 
Seek the help of Allaah and ask Him to help you to obey Him. The Prophet (peace and blessings of Allaah be upon him) used to say in his du’aa’: “O Allaah, help me to remember You, be thankful to You and worship You well.” 
May Allaah help you to do all that is good. 
And Allaah knows best.