Does anyone know of a free app for digital downloads that includes watermarking/pdf stamping?

[Gladis]

I sell art prints, but want to test selling 1 as a digital download (so, doesn't make sense to pay monthly....) I installed "Digital Downloads" from Uplinkly, only to find out that I can't watermark unless I pay to upgrade my plan.     Now spent hours reading through the other apps and just can't find one that has a free plan that includes watermarking.  thanks! 

[Rein]

Hi, @Gladis 

I have taken a look at our app store and I do not believe there is a free solution for this Specifically due to the PDF protection and watermarking requirement. 

That being said, I recommend taking a look at this list here. 

There is a selection of apps there you can look through and check what fits your purposes, some do offer free plans but as far as I could see none of those features as part of it.