He wrote "for about 20 bucks", so I suspect he spent around $20. And "maxed out my Dropbox referrals" seems to imply that he did it up to the maximum for Dropbox referrals, which is 8 GB.
You've got the first part right, but I also happen to work for a university so I associated my .edu email address to my Dropbox account. Doing that will double your referral bonus to 500MB per referral, and double your maximum free space from referrals to 16GB.
Did that happen right away that you got more space from your .edu? i put mine it and it didn't seem to do anything.
For me it did happen instantly.
Huh. Did the text that says what you get change? Like from 250 to 500? Maybe I just don't know how much space I had heh.
The text changed from 250 to 500, also my available space doubled. I didn't even get an email to tell me, it just happened.
Oh. i was just doing it wrong. doh!
I'm assuming it will be more than "about 20 bucks" once people find out about this! On the plus side its free money from Google right?