Dropbox 提供50-100G空間使用

今天收到Dropbox的一封信內容如後：

Did you know that it's easy to get more space for your Dropbox? Upgrading your Dropbox to Pro 50 or 100 lets you:
Get to your entire photo and video collection from anywhere.
Work straight from your Dropbox by moving in all of your documents.
Keep deleted files and old versions of files forever.
You can supercharge your Dropbox here.

Enjoy!
- The Dropbox Team

P.S. If you're not quite ready to upgrade, remember that you can always refer your friends for more space!

不知道是英文不好還是真的
要提供50-100G空間
上面沒說要不要費用
其他網友有收到相同信件嗎？
正確解釋為何
是否要費用？

請網友釋疑！感恩！