But lets break down what value YC offers:
Education: The Startup School videos are available publicly here: http://bit.ly/YCVideos. You can schedule office hours with YC even if you are not part of YC on https://blog.ycombinator.com/yc-open-office-hours/
Investment: A YC allum last week told me that YC's investment is really not a good deal financially, and I think he's right given where we are (we've been through 2 accelerators)
Network: This is one of the aspects that's hard to replace, but reach out to your network (get https://www.conspire.com/ ). I managed to get a lot of advice from the above YC allum who I happened to work with in banking a few years back. And also help people out! You never know how it can come back, e.g. a guy at our co-working space I helped out with some electronics last year was the designer for the original Oculus Rift and put as in touch with one of the co-founders!
A YC badge for your startup: Again, hard to replace but it just means you have to be that much better at pitching and looking for angels/advisors who are in your space. Also read Venture Deals
YC makes a lot of mistakes and most of their startups fail, they have however got some big successes and that's what makes them attractive.
Hope this helps those that didn't get in