If what you want is a quotation or offer, then sending a letter of intent makes you look ignorant while requesting a quotation will generally at least make you look like you know what it is that you want. And what you want, after all, is a price quote. Hence you want to request a price quote, via a request for quotation.
LOI as a Source or Promoter of Undue Litigation _ Aside from the legal problem of the ambiguity and uncertainty inherent in LOI, there is yet another major problem inherent in the document, from a legal standpoint. Namely, precisely because the LOI is basically ambiguous and non_definitive by nature, the document often easily lends itself to different interpretations and understandings at the hands of different parties (or even the courts), and thus lends itself, in turn, to being a fertile source for undue litigation and legal contests for those involved with the use of that document in their transactions.