This article is from the Macintosh for sale FAQ, by Elliotte Rusty Harold firstname.lastname@example.org with numerous contributions by others.
First see section 2.0 below to try and decide on a reasonable
price. Be prepared for flames if your price is too far out of line
including follow-up posts warning potential buyers that you are
trying to rip them off. You may just want to state "best offer."
That way you aren't responsible if someone else misvalues your
equipment. If an offer does come in that meets your minimum price,
you can sell it. If there are no reasonable offers, you don't have
Be sure to include a descriptive subject line in your post.
For Sale, Macintosh For Sale, and Macintosh Software For Sale are
all HORRIBLE subject lines. Better subject lines would be
SE/30 4/40, $395 or best offer
Photoshop 3.0, full edition, unopened, $250.
Then include a more detailed description in the body of the post.
Also be sure to state whether or not you'll pay shipping. (It's
much easier to sell an item if you agree to pay shipping.)
You should post your notice in comp.sys.mac.wanted and
misc.forsale.computers.mac ONLY. Posting a for sale ad to
comp.sys.mac.misc is guaranteed flame-bait, even more so if your
offer is over-priced. You should also restrict the distribution of
your message to as local an area as possible. Ask your local news
administrator for help if you don't know how to do this.
Finally if you've sold your item please don't post a message
saying the item has been sold. Most of us don't care. If you are
getting a lot of offers and want to take the item off the market,
it's better to cancel the original message. The bandwidth cost is
the same, but you'll save a lot of people the trouble of reading
two now-pointless messages from you. Again you may need to ask
your local news administrator how to do this.