Before jumping to conclusions about more expensive repairs, start by:
* Checking the battery terminals: Look for corrosion (white, powdery substance). Clean them with a wire brush and baking soda and water solution.
* Testing the battery voltage: Use a multimeter to check the battery's voltage. It should be around 12.6 volts when fully charged. Anything significantly lower indicates a weak battery.
* Trying jump starting: If the voltage is low, try jump-starting the van from another vehicle. If it starts, your battery is definitely the problem.
If jump-starting works, the problem is likely a dead or failing battery and needs to be replaced or recharged. If jump-starting doesn't work, then you might need to investigate the starter motor, ignition switch, or other electrical components. A mechanic can diagnose this further.