Photoadking looks OK at first sight - it's a freemium model - don't buy anything until you've checked it out. Canva is the market leader so check that out as well. In my experience the issue isn't the software so much as the design idea, so check out their templates. If you're not sure what you want you could always hire someone with good reviews on Fiverr for a few bucks and see what they come up with.