A Word on Certification Courses
Depending on your experience with security and penetration testing, you may want to start with a less technical certification and work up to the more intense, hands-on courses/certifications.
For example, many security professionals obtain their CEH to gain foundational knowledge of ethical hacking. From there, the GPEN could be a good second step to build on that knowledge and get hands-on experience through labs. The Offensive Security certifications are much more advanced and will require a demonstration of skills in a lab environment - these are great, highly regarded certifications to work up to.
Everyone learns differently, and you should ultimately take the path that is most effective for you, which may not involve obtaining a certification at all. If you are trying to get certified for a job, be sure to consider what skills you will need for that job and which certifications the employer values.
A Word on Training Resources
There are plenty of excellent free training resources available to you and that may be enough to get the experience you want. In some cases, you may find resources that require payment. Depending on the material and how much it costs, it may or may not be clear whether or not to pursue that course or training.
If money is a concern, see what others have said about the training resource as there may be cheaper alternatives to learn similar information or funding/scholarship opportunities available to you. For example, SANS offers its Women's Immersion Academy and VetSuccess Academy to provide accepted applicants with free training courses and certification exams.