Could be the spark plugs but, that may not be the only problem. Could be a bad battery, starter, or even the belt like the mechanic said. Take it to a trust worthy shop.
If the spark plugs are soaked in oil, then you need new spark plug tube seals and new spark plug wires. However, that usually doesn't cause a complete no start, but usually causes misfire.
Sounds like your oscillation adjustment relay solenoid positioning screw is out of adjustment, take it to a competent mechanic and have him adjust it, it should be a quick cheap fix.
Two days ago my 96 Honda Accord 4-cylinder was working fine all morning, then I added motor oil before going into the bank. after running in for 5 minutes it wouldn't start. I had to get it towed and the tow guy said "sounds like your timing belt" when I tried to start it. my dad and I were checking things out and the spark plugs were covered in oil and created no spark. what might be the problem?