46. self-study / no restrictions / what learning materials / you / use

=> Self-study has no restrictions of what learning materials you can use.
47. you / access / free courses online / famous universities / or / download free books / use / your studies

=> You can have access to  free courses online of famous universities or download free books to use for your studies.
48. self-education / allow / you / access / your learning materials anywhere / and / any time / you want
=> Self-education  allows  you to access to your learning materials anywhere and  any time you want.
49. if / you / want / certificate / completion / you / need / pay some money / but / it / not as expensive / a formal school

=> If  you want to have a certificate of completion, you will need to pay some money, but it is not as expensive as in a formal school.
50, a drawback / that / no one / available / answer any questions / but / you / your own / find / answers / you need

=> There is  a drawback  that no one is available to answer any questions but you your own have to find the answers you need.