interaction design - Giving positive/negative connotation to two textual options/buttons

I'm developing an "photo editor'ish" mobile application. After the user has finished processing their photo (such as choosing filters, shape, etc), the user should save the outcome to their camera roll.

I'm offering two options:

1. 
   

   Save for free, with a watermark on the final picture

   
   



2. 
   

   Save without a watermark (if selected, an In App Purchase window pops up).

   
   

This is how I've made it look now :

I would like to increase my In App Purchase rate. How can I make the first option look positive and be triggered more frequently than the free watermarked option?

UPDATE

This is what i went for at the end. I tried to make to top one more positive than the bottom by appending the word "Save" only to the first one –

Answer

Why are you using 'Export' word in red button and 'Save' in text Button?

I see a good approch. But Text Button looks very different, I thought it will have different funtionality. Both buttons belong to same group.

So design keeping consistency.

See above, it looks like both are clickable and are buttons.