First step - have the check engine light or stored fault codes scanned - for free - at any local auto parts store; Advance Auto, Auto Zone, NAPA. Then, post a reply as 'add answer' for more assistance.

Possible Causes of Engine Hesitation or Stumble:

Dirty fuel injectors (cleaning the injectors often fixes this)
Dirty air filter (change filter)
Dirty / clogged fuel filter (change filter)
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

Remove the ignition coils, then the plugs.

Clarify what you mean. No air blowing out or air is blowing out that is remaining cold air?

loosen plug all of the way, hook the plug wire back on it and pull it out

Engine oil leaks may often be difficult to trace. Try thes steps first, clean the engine using an engine degreaser and high pressure water spray. Remove all traces of oil, dirt, and grease to be able to view the engine and gaskets where oil may be leaking. Then, add a slight amount of engine oil soluable dye to the oil and drive like normal. The engine oil dye will show up wherever the leak is.
There are too many possibilities and locations for the engine oil to leak; valve cover gasket, oil pan gasket, front timing seal, etc.

system too lean bank 1

Check the Intake Air Boot for a crack or leak. Clean the Mass Air Flow Sensor, erase the code again and see if it returns again. A shop grade scan tool could allow live data readings which would make diagnosis easier but most people do not have anything more than the simple $30 code readers.

So what you are saying is that the engine starter is not operating. No noise other than a click when you turn the key. That being agreed to, granted nthe mengine was low on oil and you have an obvious oil leak, but if you drove to the gas station and shut it off, the engine cannot be seized. You may need a new starter. Try smacking the starter lightly with a small hammer or screwdriver while trying to start the engine. If it suddenly comes alive, then you have confirmed a bad starter.

Too much cost is a relative term; how much is too much - as compared with other repair shops estimates for the same work? Get estimates from different repair garages, for the same work as the labor per hour charges will vary even in the same locality. Ultimately, only you can decide.

Realize that most of the $790.00 cost is the labor; the parts alone cost around $82.00 for the timing component kit - including the water pump, for your vehicle = source www.RockAuto.com and www.autopartswarehouse.com. Such as the kit described, below. The water pump replacement is recommended due to having the water pump exposed once the timing belt and component are removed on your engine - the labor to replace the water pump later on would basically cost the same - again as the timeing belt replacement. Do it once for insurance purposes.

GATES Part # TCKWP284 PowerGrip Premium OE Timing Belt Component Kit W/Water Pump; 4 Components (1 Belt, 1 Tensioner, 1 Idler, 1 Water Pump)

One bit of advice - use the 'Estimate Cost' and 'Find-A-Shop' features on the AutoMD website to gain repair estimates from several repair shops in your area. Also, use the 'How-To-Guides' feature and a detailed repair manual - to get familiar with the repair and what kind of work is involved to replace the timing belt and components on your vehicle.

Typically, I'll pay anywhere from $150 -$300 for a timing belt replacement every 60k miles for my front-wheel drive four cylinder car; this price includes the timing belt, belt tensioner, related pulleys, and water pump - plus all the labor.
It pays to shop around - once you find a shop with a good reputation and are word-of-mouth recommended - stick with them.