Has a 250,000 words monthly limit on the “Turing Spinner” and a 2,500,000 words monthly limit on the “Standard Spinner”. Anything above that will be charged additionally ($10 per 1,000,000 words for the “Standard Spinner”, and $3 per 10,000 for the “Turing Spinner”). However, they do offer custom plans for heavy API users – all you need to do is contact them.
I've ranked websites in the past with spun content, and now they are still on #1 position of google. First year (2014) google found me because my spun was really bad, many paragraphs were just copied and my position drop from #2 to around #20 after a panda update. Later I cleaned all my text with better spun (I didn't buy any article!), my ranking went up again, and with more backlinks I reached #1 and it is still there