Starting tonight, all Dropbox plans are getting upgraded. From the blog post:

Dropbox Pro now comes in flavors of 100 and 200 GB, but at the price of the original 50 and 100 GB plans. For those of you who need even more space, a brand new 500 GB plan is also joining the posse! If you’re already a Dropbox Pro subscriber, just take a seat and enjoy the fireworks — your Dropbox will supersize itself automatically tonight.

100GB will be $9.99USD/month or $99USD/year. 200GB will be $19.99USD/month or $199USD/year. No pricing yet on the 500GB plan, but presumably it'll be $40USD/month or $400USD/year?

As a paying user of the 50GB plan, I love that they're just throwing in double the space for the same price.

Sign up here and I'll get some free space and so will you.