Depends on: (1) What it's worth, (2) What you can afford, and (3) How much you do or don't like it.
First point: A house priced at $285,000 could be worth anything. Ask your agent for a CMA (competitive market analysis) of the property, along with his/her analysis of the house's value. (Unstated in your question, but a common thread, is: "If a house is priced at a certain figure, is there a certain percent below that that I should offer?" No, there is not.)
Second point: How much can you afford? If you can only afford $250,000, then that's the most you can offer, regardless of its value. (Well, there are some exceptions, but practically speaking don't offer more than you can afford.)
Third point: Does the house fit you and your lifestyle. It might be a great house for, say, an elderly couple that wants everything on one floor, only needs 2 bedrooms (one for themselves, one for visitors), and so on. But it might not work at all for a family with 4 children.
Hope that helps.