If you're interested in the property, feel free to offer as low a bid as you believe, the seller might be willing to accept. Do your homework. Know what the real current-day value of the home is, before making your offer. Know what other very recent sales have sold for and that should help you formulate an offer.
If they're insulted, you can always increase your offer, if you determine the value is there. But you might get lucky, and they may be motivated enough to accept a low offer.
Hope that helps.