Thing with these Memes is that the watermark doesn't detract from the meme's joke and most memes are old video catpures and super pixelated anyways, so who cares?
I use an app with a similar name (MemeTastic, but it makes those image macros, though), but I don't need to pay anything AND there is no watermark on any meme!
Android: power button and volume down button simultaneously
Windows: "Print Screen" button on your keyboard (sometimes shortened to Prt Scr, located at the top towards the right between "Insert" and "Pause/Break") and paste into MS Paint or whichever photo editing software you use
Windows: “Print Screen” button on your keyboard (sometimes shortened to Prt Scr, located at the top towards the right between “Insert” and “Pause/Break”) and paste into MS Paint or whichever photo editing software you use