Buying Star Trek DVDs on eBay allows one to save a great deal of money.  For example, the North American release of Seasons 1-7 (the whole series) of Star Trek: The Next Generation goes for $450 at Best Buy and $315 at Amazon.com.  But it's possible to get the series on eBay for $200.  The following guide will list the maximum bids you should enter if you want to win a Star Trek DVD series at the lowest possible price.  This guide is based on 6+ months searching through and purchasing Star Trek listings on eBay, testing at over 50 auctions to determine the lowest possible price, and browsing through completed listings.  This guide reflects prices as of late 2006.  It is very accurate, though you may have to wait up to a month to get the prices listed.  But before we begin, there are a few things to remember.

1) Don't buy Asian import DVDs.  You will spend nearly the same amount of money for a vastly inferior product (See my guide Spotting and avoiding Asian import Star Trek DVDs).

2) Don't buy the seasons individually.  You may think you can save money buying the individual seasons separately.  But remember that the cost of shipping each season is about the same as for shipping one set.  So instead of paying $10-15 shipping for the whole set including all the seasons, you'll end up paying $7.50-10 shipping for each season separately.  This means, for a seven seasons set, adding about $50 extra to the price.  So it's cheaper to buy the set all together.

3) Bid on auctions, not in stores or with "Buy It Now".  If a seller is using the "Buy It Now" option, the price will be set at the maximum that any buyer is willing to pay.  Only with an auction (or occasionally with the "Best Offer" option) will you pay the real selling value of the item.

4) Don't buy used.  You can purchase new items on eBay for as little as 10-20% more, but you can be much more certain of their quality and condition.

5) Look for an auction in which multiple items are being sold.  In an action with 5 items, the final selling price will be significantly below that of an auction with 1 item.  You may even be able to buy at prices lower than those listed here.

So, what maximum bid should you enter?  It depends on the series.

Star Trek: The Original Series (Seasons 1-3)

Best Buy: $179.99
Amazon.com: $175.98
Your maximum bid: $120.00

There are a lot of auctions out there which offer the "Buy It Now" option for this series, usually for $149.99.  You can save $30 by bidding on a few auctions, but many sellers are lowering their "Buy It Now" prices to remain competative.

Star Trek: The Motions Pictures (20 disc set)

Best Buy: $124.99
Amazon.com: $81.78
Your maximum bid: $70.00

Note how cheap the item is at Amazon.com.  Some eBayers will purchase the whole set with "Buy It Now" for as much as $120.00.  Why bother?  Remember, don't buy it if the shipping puts the price over $80.00.  Also, remember to only bid on the 20 disc set, not the 15 disc set or any other.

Star Trek: The Next Generation (Seasons 1-7)
Best Buy: $442.83
Amazon.com: $315.00
Your maximum bid: $220.00

This is where the real savings comes in.  Using eBay, you can save $100-200 from the lowest retail / other online prices with this seven season set.

Star Trek: Deep Space Nine (Seasons 1-7)
Best Buy: $442.83
Amazon.com: $365.99
Your maximum bid: $200.00

Although this set is more expensive than the equivalent Next Generation set on Amazon.com, you can probably get it for a bit cheaper on eBay.  In auctions with multiple sets up for sale, it can sell as low as in the $180s.

Star Trek: Voyager (Seasons 1-7)
Best Buy: $696.98
Amazon.com: $348.50
Your maximum bid: $250.00

Voyager is easily the most expensive Trek series, and it's actually quite hard to find on eBay.  This is because the retail prices are so high and because it is the favorite series of sellers of Asian imports.  The prices for this series vary widely, typically ending up in the range of $350.00.  But they frequently sell for a bit under $300.00.  You may have to wait a while, but $250 is a fair price for this set.

Star Trek: Enterprise (Seasons 1-4)
Best Buy: $407.98
Amazon.com: $250.00 (Not offered directly; sum of individual seasons)
Your maximum bid: $120.00

Like Voyager, the fair price for this series isn't totally clear yet due to the glut of Asian imports and the rarity of the US set on eBay.  But $120 is a reasonable price for the set.

Use of this guide should allow you to participate wisely in several auctions and eventaully win the Star Trek series of your choice at the best possible price.