Confusion with In App Charges – Photo Editor: Blur Backgrounds Review

I just recently downloaded this app and edited my first photo. Love the background blurring effect-but to remove the watermark there is an in app purchase fee of .99 or you can pay 3.99 for all access. My question is-is this fee per photo you edit or is it a one time fee and then you can edit as many photos as you want -with no watermark. If you pay the $3.99?
Review by baileyroxie on Photo Editor: Blur Backgrounds.