3 possibilities:
1. Loose power cable (highest possibility)
2. Dead battery
3. Alternator problem, or loose connecting cable (will cause dead battery as side effect)
1. Tighen battery connector nuts at the black and red cables. Could be due to cloose cabling (free)
2. If you have a friend who has car battery charger, charge battery for > 3 hr(free).
3. If no battery charger, get a used one for $20, and charge battery for > 3 hr ($20)
4. Measure battery voltage before and after started up the car. Ensure voltage is above 12 V (12.8 V). This isolate alternator problem, but not loose cable
5. Bring to any car workshop, and charge for 1 - 2 hr with battery stress test, then another 1 - 2 hr ($40). This isolate a dead battery
If you think these is too much for you, send to either regular workshop or dealer. It could be a simple $50, or $600 repair (dealer)