Well, the value of a 1994 Elantra isn't much.  It's probably worth
investing a little money to have it diagnosed, but I wouldn't spend more
than about $500 on it unless it's in exceptional condition.  

Right now I have difficulty guessing whether the white smoke is a fuel or
engine related issue, and whether it's related to the not starting.  The
possibilities are great.  It could be something as simple as a coolant
temperature sensor (not a big deal-- fix it) or as bad as a stripped
timing belt (probably not worth fixing).