The quotation warns that a low price does not make an unnecessary purchase worthwhile. Something bought only because it appears inexpensive still consumes money and may provide little practical value. The word “dear” carries the sense of becoming costly: an apparent bargain can ultimately represent waste if the buyer neither needs nor genuinely wants what has been purchased.

Jefferson included this advice among his practical rules for everyday conduct in his letter to Thomas Jefferson Smith. It follows other guidance about spending only money already possessed, placing the maxim within a broader emphasis on financial restraint and careful judgement. The principle distinguishes price from value and encourages people to consider usefulness before cost. Applied more broadly, it cautions against allowing discounts or apparent bargains to determine purchasing decisions when the underlying item has little personal value or purpose.