To subscribe to a Transifex plan:
Click on your organization drop-down menu (next to your profile icon).
Click on Add a credit card and enter your credit card info, as prompted.
Choose one of the plans and subscribe.
If you are interested in one of our enterprise plans or need help in choosing the right plan for your localization efforts, you can reach out to us for further assistance using our contact form here: https://www.transifex.com/contact/