I'm running SmugFTP on my own. Smugmug does not subsidise me. For SmugFTP to remain sustainable, I need to charge. I'm unable to pay for everyone's bandwidth. Hope you can understand. =)
New users who sign up can upload 1GB of files via SmugFTP for free.
SmugFTP charges a flat rate of 5GB per dollar for uploading.
Credits won't expire.
Running out of credits
If your credits ran out, you won't be able to upload.
Payment can be made at the credits link after you logged in.