But doesn't NameZero charge to transfer too?
I don't have a domain with NameZero so I can't say for sure, but I haven't heard of any registrar charging you for transferring away from them [*]. Either way, make sure your current registrar does not have a "lock" on your domain before performing the transfer. At best, this may delay your transfer quite a bit, and at worse, it may cause your transfer to fail completely (in which case registerfly.com would still charge you for the transfer fee even though it didn't complete!).
[*] Now that I've thought about it for a bit, I don't see how NameZero could charge you for the transfer since it's the other/new registrar that is carrying out the process. What NameZero could do though is not cooperating with the new registrar (perhaps by refusing to remove your domain lock, if any), and thereby holding your domain hostage, but this is the worst-case scenario. I'm not a registrar and don't play one on the Hot Deals Forum, so YMMV.