William D. Lynn of Falls Church has been one of this column's faithful correspondents for many years. He is interested in - and knows something about - many subjects.

One who must find fresh ideas to discuss each days is grateful to have readers who stimulate his thinking.

The latest from Bill Lynn is about the Postal Service's stamped envelopers. In the old days, they cost one penny more than a first-class stamp. Later the extra charge for envelopes doubled (to 2 cents). Now, says Bill, each envelope costs 3 cents. That's a ripoff, he says. Excessive.

Inasmuch as the Postal Service itself isn't always able to figure out what its costs are, I do not propose to challenge whatever justification it offers for the 3-cent rate. However, there are several points that probably ought to be mentioned in this context.

First: If the surcharge for a stamped enveloped was a penny when first-class postage was 5 cents, and if that surcharge is raised to 3 cents when the cost of first-class postage goes up to 15 cents, the ratio between envelope and postage costs remains the same.

Second: The labor costs involved in the manufacture, shipment, storage and handling of envelopes have unquestionably increased. Printing definitely costs more and glue probably does, too.

Third: When I was a young reporter, I heard a publisher inveigh against the greedy rascals who had just raised the cost of the rolls of paper on which his newspaper was printed from $32 to $36 a ton. The last time I looked, newsprint was selling for $320 a ton. Facial tissues have become to expensive that it costs me 10 cents a day just to keep my reading glasses clean. A head cold can bankrupt a man. When you hear the claim that paper towels absorb more now, believe it; they absorb more of your household budget.

Under the circumstances, I would guess that USPS can make a good case for raising its envelope prices. I don't know if 3 cents is too much, but I wouldn't give you 2 cents for my chances of winning the argument.