Is it the timing belt or the crankshaft sensor?

My car will not start. It is a chrysler concorde 1999. I bought it in march...and it was running fine. Then one day...It took me 5 trys to start it. It was turning over but it wouldn't start. then it ran fine for a couple of days. Then I drove it about 80 miles...and went to start it the next day...and it wouldn't start.It still turns over...but wont start. We had 2 people come listen to it...they didn't really get a chance to actually "look" at it. One said it was the sensor, and the other used a tester thing on it...and said no codes came up so it had to be the timing belt. :/ anyone have any ideas? I'm tight on cash right now...so I'm really hoping its not the timing belt!