Won't Start

So night before last I went to town to get
some things, turned my car off threw the
keys in my purse, 30 mins later I get in my
car and try to start it, and suddenly it starts
stalling out and dying. Sounded as if it was
out of gas but it wasn't, so I keep trying and
eventually it starts up after I stayed on the
gas hard. So I went home ( the car ran and
drove great as usual) so I killed it and didn't
think nothing else about it. Got up yesterday
and got in the car, without hesitation or any
problems it started right up so I'm thinking
we're good. Go inside Wal-Mart come out 20
mins later and again it wouldn't start but this
time it would only crank or turn over but
wouldn't start for nothing it acted like it
wasn't getting fuel so I left it parked over
night and disconnected my battery and
called my daughter to come get me. Went
back this morning and it still won't start up.
Had the battery tested and its fully charged,
fuses all seem good, relays look good as
well. Has plenty of gas, sounds like the fuel
pump is kicking on & oil doesn't smell like
fuel I'm at a loss and stumped. A guy at Wal-
Mart said it it could be my timing. But the
car hasn't been acting up or doing this, it
was just sudden, never any problems.
Someone please help..  Open to all advice
and any suggestions!

Also I priced all the parts below and was
wondering is $70 $75 was a good price for
everything listed below and its all new..
Timing kit, water pump, serpentine belt, fuel
pump & strainer, 2 relay fuses, 6 spark plugs
and a oil filter with 5 qrts of oil.. Good price
or no?