In general, is there a percentage of return train resellers ask for?

IMO, you can't generalize.  Some items will command a larger percentage of their original price point than others.

Hopefully if you go via an auction house, they will group items such that some of the lesser desired pieces will be grouped with higher desired pieces, thereby getting them sold.  Selling all one by one will result in the "hot pieces" going and you left over with all the generic stuff no one cares enough about to buy.  (a problem known as "cherry picking" if you were to try to sell a big collection and someone only offers to buy certain pieces)

Search eBay completed items (sold ones) for items you are trying to sell to see what someone (at least one person) has recently been willing to pay for such an item.  You may not easily always get that same amount, but it's better than guessing.  You could look at a price guide too, but those will probably suggest higher than realistic prices you may realize as a private seller.

-Dave

In my experience with auctions they are all different. The same item can bring different prices even at the same auction let alone different auctions 

Probably train shows would be the best place for you followed by eBay and then auctions to sell your trains price why. Just my opinion others may disagree. Although at some train show you may need a resale license 

I'd say your best bet is ebay. You can figure that 1987 and up used train items sell for about half of the new price, but that also depends on condition. I haven't followed TCA for several years, but the "For Sale" section in their quarterly flyer was also a good pricing source.

EBay sold items would probably the top price you could expect.  It's an auction to a world wide audience which you may or may not have access to.

TCA magazine prices generally are very unrealistically high.

Train show prices are geographicalmy sensitive.  On the west coast BAR, PRR, NYC wont sell well as well as SP, UP, SF, WP and other western lines.  On the east coast it will be reversed. 

Not being in a hurry is a good thing.  However, there will be fewer buyers tomorrow than today and a larger supply of trains available 

The price guides are just a dream of what that certain company wishes their trains were worth.  

Reality is what they sold for in the last week (EBay).

In the end there is no magic number, no formula, to selling anything,let along train gear, it boils down to what you want to sell something for and what people are willing to pay.  If you are buying items then trying to resell them for a profit, it is very different from thinning out or getting rid of what you have. If you are buying and reselling to try and make money, then you need to decide what percent profit you want to try to make and go for it (and know with some you may be able to get more than that, others you may lose money on). If you are thinning out your herd, Take the items you wish to sell, and as others have said take a look at things like the Greenberg guides, take a look at ebay and other auction sites, take a look at what stores that sell used stuff online want for the item (store prices aren't necessarily realistic, there are stores that sell stuff way, way over what you would get at a train show for it, they have a clientele that doesn't care, but online stores have competition), and then decide what you feel it is worth. Put it out for consignment or auction or on ebay or on here, and see what happens. If it sells, great, if it doesn't hit your reserve, give  it another shot later on, or revise your expectations. If you have items you just want to get rid of, think of doing a bundle, where you price the bundle at the price you want to sell a particular item at (for example, let's say an engine you want 600 bucks for......put it up for sale with several freight cars you wouldn't ask a lot for at the 600 bucks, might sell easier than trying to get 600 bucks for the engine alone, the buyer thinks they got a bargain, and  you get the engine at near the price you wanted. 

Prices change all the time, car auctions are famous for that, at one auction a car your figure  is common and not that great from a collecting standpoint goes for a high price because a couple of people bid against each other, in another auction a car that should be high priced doesn't sell. 

If I understand your question, you are asking how much a reseller would give you for an item that you think will sell for $100. The seller usually has an inflated view of what something is worth or will sell for. If the reseller buys it from you, I would expect that reseller to offer 35-50% of what he thinks he can get out of it.

If it is just on consignment, probably 30% of final selling price. Just guessing.

I need an “eBay for dummies” approach as I don’t know what fees or commissions are involved. I love BIGKID’s suggestion about including cars since I have a large collection of freight and passenger stock, many without boxes (way to much storage space required).

Thanks everyone...Rich

I think everyone ponders this question:  how to maximize the return when selling your collection.  Selling on ebay is tough, there is a lot of competition and then you have to pack and ship it all.   Large re-sellers as stated previously will most likely yield 30 cents on the dollar.   Make a  list of all your items and judge an average price for each item based on the same items for sale at train shows.  Next, rent some tables and price to sell. Oh, and make your tables stand out.  You don't want to be just another table.

The fees for eBay and PayPal are 15%. If a seller over estimates what his items for sale will get i would assume they will not be in business long. Personally I like to be on the low end of what an item may be worth. Sometimes this means that I pass on what may be good deals but I rarely lose on what I do buy. Although sometimes I do.