Answer

There is always normal condensation.. it takes a few secnonds (to minutes) to clear out of the exhaust. Then there is coolant entering the cylinders.. and then there is oil entering the cylinders.
Coolant smells sweet, oil smells burnt.. and condensation.. just smells like exhaust.

So a good way to go about it is... How does it smell?

Smell Oily?
OK.. rule a few things out..
So look in the throttle and see if oil might be coming into the engine from there. This would indicate a problem with a turbo, or a crankcase ventilation system problem. These things will usually cause other problems though, and the engine would use oil.. which you mention there is nothing like that... does it use oil?

Another thing, look at the oil.. if it is dark and nasty, then this is evidence that the car was used for a bunch of short trips, and there will be sludge in the engine oil galleries. This can eventually damage valve stem seals and guides from overheating them.... as well as damage bearings, which will cause fluctuations in the oil pressure, or just a generally lower than normal pressure condition...

So, if it turns out to be valve seals.. expect it to be on an intake valve. I can show you a video about ..why, but won't really go into the pressure differences and such.
Either way the head will need to be removed, if you cannot get an overhead spring compressor on the springs. The camshafts would have to be removed if you can get the overhead spring compressor on it, though.

Smell like Coolant?
Another thing that would cause this situation is of course engine overheating. Of course you got the car from ebay.. and have no way of knowing if it ever overheated in the past. Overheating is bad because the different metals expand at different rates. At this point a cooling system pressure test is in order... OR ou can always open the cooling system and fill it completely up.. pull out the spark plugs, and bring the cylinder to top dead center on compression stroke (very important), and then spray compressed air in the cylinder and pressurize it that way... all while looking at the coolant fill for bubbles.. which would be cause enough to pull the head off th engine for further inspection.

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Anyways, if the exhaust doesn't smell right, then move on to looking at the spark plugs. See if there are any fouled with oil or coolant.
Once you find out what is wrong.. I can most likely provide instructions (or a price range) for the repair... if one is needed.

Hope it helps!