This one seems crazy. Why worry about offer and acceptance? If a sale happens, offer and acceptance happen. The answer is that this is the most critical "boiler plate" because it drives everything else. Almost all Standard Terms and Conditions do everything in their power to make their owner the Acceptor not the Offeror. Why? Because a contract is formed when and where the acceptance takes place. The last party to speak controls the terms. If Seller says I'll sell you 10 widgets at $10 a piece on my terms and the party receiving the widgets simply sends the money and takes delivery, the Sellers terms govern no matter what the Receiver's initial inquiry said. In converse, if the Receiver in the example above sends payment and a purchase order which says I agree to buy on the terms of this purchase order only and the Seller simply takes the money and delivers the widgets, the Receiver's terms govern.
This game does not always work. If the quote, the purchase order and the invoice all say they are the acceptance (and they often do), at least two of them can't be right. It is still best to try to be the last party to the contract even if you are soliciting the sale. Sometimes it will work and most times it will at least negate the other side's attempt to force its terms on you. (If the forms are conflicting, any term not in both forms drops out.)