Is an interview worth travelling for?

I got a call last night from a headhunter agency and said I am due for an interview in two weeks. Said interview will be in New York and I am currently in Florida right now. They instructed me to arrive a day ahead and report to their agency as soon as I land. More or less I’ll have to stay there for 3 nights and 4 days for the interview and some paperwork. That’s like almost $800 to spend and I am not that loaded. In fact, I’ve been saving for a multiple city singles tours in Europe this October. So should I gamble the $800 and cross my fingers that I would get the job or should I just pass on the opportunity? It’s a 50-50 to be honest. It’s not really guaranteed that I would land the job. I need a good advice.