There are free and premium versions of GradeProof you can choose from. The free version comes with basic features only: spelling engine, grammar engine, and custom dictionary. The premium version includes the basics but also includes an advanced grammar engine, eloquence engine, and plagiarism engine.

Try Now Online Correction
As the name states, this tool is an online grammar and punctuation checker. It allows finding grammatical, spelling and stylistic errors in your text. If you open the web page of that tool, you will get a minimalistic text editor where you can enter the text you want to proofread.