best offer

[mmangino-2008]

What exactly is a best offer? Can I offer anything and the seller is obligated to sell?

[toby_le_pue]

No you cannot.

You make your best reasonable offer and the

seller can or reject it.

The seller may make a counter offer and you may

accept or reject it.

http://pages.ebay.ca/help/buy/best-offer.html

[reallynicestamps]

Further -- you can only make an offer on a listing which states that the seller will entertain Best Offers. 

Making BOs to sellers who know what they want for an item may put you on their Blocked Bidder List or have them Report you to eBay for a Violation.