Last week we ran a question from a consumer who wondered where she could buy pre-printed (with the name and return address of the sender), pre-stamped envelopes. She wanted to give them to her mother and her aunt for Christmas.

We searched in vain. We couldn't locate a company that sold them.Little did we know, the answer was under our nose. (Sherlock Holmes we are not.)

Many of our readers called to say the envelopes are available through the U.S. Post Office.

We called the Post Office to confirm. A spokesman said order forms are available at all post offices. A fulfillment house in Pennsylvania fills the orders.

The order forms currently in post offices don't reflect the new 32-cent postage rate, effective Jan. 1, but envelopes being mailed to consumers now have the "G" stamps on them. Consumers will be billed for the difference.

The price of the envelope and the pre-printing is a bargain. For example, an order sent in by a Salt Lake physician's office for 500 envelopes breaks down to 3.2 cents per pre-printed envelope, plus the cost of the stamp.

Where is DPC?

Here's another follow-up from last week. A consumer wondered where a company called DPC was located. He had ordered address labels from the company and hadn't received them. He had forgotten to keep a copy of the company's address.

We called the Direct Marketing Association in New York City, a mail-order trade group. It said DPC was not a member.

We also consulted a directory of mail-order companies and it was not listed there.

We did track down two companies in the Washington, D.c. area with the naem of DPC. One was a general contractor. The other was a data entry firm in Virginia.

But in response to our column, several people called us with the right DPC's address. It is P.O. Box 12268, Roanoake, VA 24024-2268. Its phone number is 1-703-342-7801. Address label cost $4.30 for 250 and $5.95 for 500.