I want to add one other thought or two. Correct me if I am wrong. I'm new to this.

By sending 1, 2 or 3 chips via "letter" rate, the savings are considerable -- over 50 cents. That adds up over time if you are a busy chip trader/seller.

Let's say you are mailing three chips that weigh over 2 ounces. So you are paying three ounces of postage due to rounding. There are three ways to send them first class mail:
¶ "letter" (not over 1/4 inch thick) rate for 3 ounces is $0.75.
¶ "large envelope" (not over 3/4 inch thick) rate for 3 ounces is $1.14
¶ "parcel" rate for 3 ounces is $1.47.

Now, sending it letter rate, the letter is probably non-machinable because it is rigid, uneven, etc. (see http://pe.usps.com/text/dmm300/101.htm#wp1039555+ ). So if a "letter" is non-machinable, you pay a 17-cent surcharge, which brings the total postage cost to $0.92 (because $0.75 + $0.17 = $0.92). Now, you might think $0.92 isn't much different than $1.14, so why not send it as a "large envelope"? The answer is that even if you get the letter to be under 3/4 inch thick, the "large envelopes" (also known as "flats") must be flexible, uniformly thick, etc. And if the envelopes have these problems ( too rigid or uneven), you DON'T get to pay a 17-cent surcharge. Rather, you are bumped up to the "parcel" category where you pay $1.47 for the 3-ounce thing. The difference between sending the three chips via "letter" rate ($0.92) and "parcel" rate ($1.47) is considerable -- $0.55.

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I spruced up my English on my original post. You can't edit posts on this bulletin board, so I am throwing it out here:

I present this old-fashioned way of sending one or a few casino chips through the mail. It is easy and cheap, probably the cheapest. I'm so impressed with it that I post it here as a fresh thread so it won't be overlooked.

I thank Jim Gagnon for his post and thread about using cohesive corrugated cardboard wrap to mail chips to keep the postage cost down. Click this link to view that thread:
http://www.thechipboard.com/cgi-bin/bbs521/webbbs_config.pl/noframes/read/634014#m_634014
The key thing seems to be to both protect the chip(s) and keep the packed envelope at less than 1/4" thick. (There are now three categories of first class mail: (a) "letters" are the cheapest to send, but must be less than 1/4" thick; (b)"large envelopes" (flats) are the second cheapest, but must be less than 3/4" thick; and (c) "parcels" are the most expensive and can be over 3/4." It seems that the good old bubble wrap envelopes will be classified by the post office as "parcels" regardless of thickness.) Reading the thread prompted me to think about the problem, and I came up with this easy solution.

As the picture below shows (it is probably unnecessary to have the picture, but what the heck!):
1. place the chip or chips on a piece of paper.
2. keeping the chips touching but not overlapping, fold the paper over the chips, encasing the chips.
3. tape the resulting little bundle.
4. tape the bundle to the letter, fold in thirds and place in the envelope. (I like to tape the two sides of the envelope too).

Doing it that way, the envelope won't exceed 1/4 inch thick. You just pay the letter rate plus 17 cents extra for the non-machinable fee. The chips are very secure. You save paying retail the 25 to 30 cents for the cohesive corrugated cardboard wrap per mailing (but much less [about 6 cents] if you buy a roll/quantity). The chips have a little less cushioning my way, but (1) that helps in keeping the thickness under 1/4" (and I wonder if the extra cushioning of cohesive corrugated cardboard wrap would push the thickness over 1/4"); and (2) since you are sending only non-valuable sturdy casino chips this way, the rare cases of breakage (which could happen even with cohesive corrugated cardboard wrap) are easily outweighed by the savings in postage and not buying the wrap, over the long run. One disadvantage to my method is that it is a little more time consuming than the cohesive corrugated cardboard wrap way.

In the thread, I also liked the ideas about using cereal box cardboard and Starbucks coffee cup holders.