So, I think that one reply to this post would be sufficient if I get a good enough answer, but what does the actual monthly listing values account for? For example, does the price sold for an item include the cost of shipping, or is it just the original price? ALso, just exactly how accurate is the average compared to real world? I never seem to find sets that come even close the the monthly average on ebay, so someone please give me an insight on where the data comes from.

So, I think that one reply to this post would be sufficient if I get a good enough answer, but what does the actual monthly listing values account for? For example, does the price sold for an item include the cost of shipping, or is it just the original price? ALso, just exactly how accurate is the average compared to real world? I never seem to find sets that come even close the the monthly average on ebay, so someone please give me an insight on where the data comes from.

Check the FAQ

http://www.brickpicker.com/index.php/frequently_asked_questions

Where does the data come from for the values of the Lego sets?

The data is obtained directly from eBay.com through a partnership called Terapeak. We pay a yearly license in order to obtain the data.

How often is the data for the guide updated?

The data is updated once a month, usually by the end of the first week of the new month. We need to wait until eBay delivers all the files for the previous month before we can start the process of aggregating all the prices for the sets.

Do the Price/Set Guide estimated values include shipping costs?

No. This is a topic that brings much debate. Our thoughts on this topic was to remove the volatile shipping costs from the calculation. A LEGO set sold to a person 10 miles from the seller would have a different shipping cost than the same set sold to a person 10,000 miles away. Most major retailers do not include shipping costs when describing a LEGO set for sale. It is a special or deal at times to get

I never seem to find sets that come even close the the monthly average on ebay

Lets take a look at the good 'ol #10179.

The price guide has it currently at: $2736.44 (USD)

Now take a look at recent completed listings on eBay: #10179 Completed Listings

There are new and used listings there and you will see plenty that fall within those parameters

Now for a current retail set, that is mid priced and popular, lets look at Tower Bridge #10214

The price guide has it currently at: $216.69 (USD)

Now take a look at recent completed listings on eBay: #10214 Completed Listings

Again, you will see a range of recently sold sets from $169 - $299. Why people are paying $299 I don't know, but it is a sold sale that is available for us to plug into our numbers. But I think you can see that the range of prices will show that our number of $216 falls right in the path of those sold listings.

Remember that the current data in the price guide is from April, so its a few weeks behind and some sets may change, but most move 2-5% in either direction.

I decided to go with 2 posts to answer your question, but I hope it does answer it.

The biggest reason for the variation is that ebay sellers often charge either realistic or very high shipping costs for many of the listings, these are not factored into the final sale amount on Brickpicker. Conversely, we are all used to getting just about whatever we want from the major retailers for either free or marginal shipping rates. I have seen the tower bridge sell on ebay for $160 before, but they charged $75 for S&****, this would never happen from a normal retailer, you can buy it from a number of retailers for $240 with free shipping.

I wonder if these answers satisfied the OP?

Sorry for the late reply. But, yes, thank you for your detailed answer.

I tried a forum search for "sales trend chart"  and "monthly listings value".  This  post was all that I came up with.  I have a question regarding charts for sales trends. Reviewing the monthly listings value chart I see that it covers a time frame for 1 year, is this the same 1 year data that is reflected in the "1 year" performance line of the "pricing and performance information" chart? I just want to make sure that I am looking at the same starting point while cross referencing.  Thank you