Error-checking services required

Hi, my name is Oleg and I am from Russia. I am a writer of my own articles for my website in English but I need a native English speaking person to make error-checking of my texts. Text are usually 6000-7000 symbols concerning HR services and aptitude tests. I have about 20 of them right now and plan to add at least 2-3 weekly. Please let me know if you can help and what would be the pricing anf timing. Thank you!