The Letter of Intent is not binding, and rather silly at the worst of times. An LOI by definition only registers intent to purchase, and it specifies this intent weakly, and due to its ambiguity should be avoided.
But intentions are not binding contractual conditions. Nor need they lead up to binding contractual conditions. Moreover a letter expressing intent, in its form, does not adequately suggest what the appropriate response should be. Whereas a Request for Quotation / RFQ quite literally is a Request. For a Price Quotation. Hence the document's name, it meaning is expressed by it's name. Hence an appropriate response, for a vendor or supplier, is issuing a a price quote.