Sharing my favorite source of graphics: www.VectorStock.com . Pre-pay for "credits" then use them up as you purchase. Most graphics are 1 credit ($1 each). Graphics come as zip files which contain 4 formats: AI, JPG, EPS, & PDF. You can open the AI and EPS files in Adobe Illustrator or Inkscape as layers you can edit (change wording etc.) VectorStock is a nifty site, easy to navigate, save to galleries, and NO annoying ads like the "free" sites.

Above you can see the "Happy New Year 2016" graphic I just purchased for $1, along with 4 others in my cart I was comparing.
P.S. Remember to upgrade to an expanded license if needed (if you are using as the main graphic for your product).