Yes. Originally, 50$ = 1 Donation Credit, according to http://playdreamerro.com/?module=pages&action=content&path=donate, it will have 100% value. So your 50$, will indeed have 100 Donation Credits.
If you want the best bang for the buck, I think going for Spirit of Heroism (check the details here: http://www.playdreamerro.com/wiki/index.php/Spirit_of_Heroism ) is the way to go:
But if you just want an Elite Character, you can checkout the rest of the available Donation Services:
http://www.playdreamerro.com/wiki/index.php/Donation_Services
If you have any questions, you can directly contact admin Haze by logging a support ticket: http://playdreamerro.com/support/open.php