Ok, I just signed up and I know I shouldn't ask for an estimate or prices but what I want to know is what I am getting myself into, and if it is too big or too expensive of a job...

here's the story I am under contract to purchase a bank owned home, they do not disclose any problems but by random "luck" I found out the previous owner of the home. She told me about an electrical problem that sounds scary and I don't know if I even want to pay for an electrician to look at it (no one will do a free estimate) or just back out of the deal.

this is what she told me, no more info available as I have not lived in the home: the electricity in the entire house goes out randomly, no breakers flipped, but when she turns the main electrical shutoff, off, then back on, the electricity comes back on but sometimes only for a half hour sometimes longer. The house was built in 1918, I have no info on any updating. What are the possibilities of what could be wrong... could the entire house need to be rewired?

Maybe no-one can help, without more info, just feel lost here. Thanks for your time.

Sounds Like The Main Breaker, The buss(what the breaker plugs onto), loose wire.
This should? Not take more than a hour to check, Pull Main breaker check buss, Could be in disconnect.
The problem with Intermittent problems is, it may not occur during testing.
Since the connection is making and breaking, it is likely heat may be felt at bad connection.

If it's knob and tube wiring, it would be wise to re-wire. Many insurance companies require breakers to be insurable.

If this was a modern day home, then a likely cause is a loose connection on a power feeder. If could be on your side or the power company's side. Usually no cost if on their side. Your side: It depends on what they find.

You failed to mention if the house has breakers, 3 prong outlets, knob and tube etc.

Yes on 3 prong outlets, and breakers, there is a breaker box inside and another outside that has a main shut-off. Not sure what knob and tube wiring is

Don't be penny wise and pound foolish. Get and assesement and estimate from a electrical contractor. Just figure it as part of the cost of the house.