Off course not!
If you really want to participate TC50, you should try everything else. Talk yourself into TC50, leave a comment on every TechCrunch article for the next 14 days and ask for a ticket or an invite, wait in front of 635 8th Street and pitch to angel's you recognize the day of the conference, dress like a Janitor with an old college ID and a van to get in.
Invent something but do not spend 3K just to be on the DemoPit. The area no one cares about that day anyway. Leave the 3K in your bank account and be happy to have more runway, or get a freelancer to do "that thing" that will make your product that much better.
Basti.