This guide has the Reprap "Prusa Steel" printer listed, and says it is $500, with a 9.1 rating. However, I strongly recommend the acrylic version made by many Chinese electronics companies which sell for $220 for the same print quality.

I have been using one of those for the last few weeks and I couldn't be happier with it. It all works much better than I expected for the price, and has been suitable for printing various home items and custom robotics parts.

You can find them on AliExpress (the consumer-oriented version of Alibaba): http://www.aliexpress.com/wholesale?catId=0&initiative_id=SB...

If you want to get into 3d printing but don't want to drop $1k+ on a printer, try one of these.