You said that your company distributes books for self-publishers. Can you explain how this works?
First, thank you so much for giving me something else to talk about! When I said I'd talk about contracts, I didn't think far enough ahead to realize that it would mean days upon days of really dry and boring stuff, all on the same topic! I like some variety here.
If, for whatever reason--and there are lots of legit reasons--you have determined to self-publish, you will need a distributor to represent and sell your books to the LDS bookstores. Rarely will a bookstore work directly with an SP. It just costs too much in man-hours, bookkeeping, shipping, etc. Not to mention that there are a lot of poor quality SP items out there and they generally will not sell well.
If you decide to go the SP route, #1 most important rule: Get an agreement with a distributor BEFORE you print your book! They can then help you find editors, typesetters, designers and printers who are reputable and do good work for fair prices. It breaks my heart when someone sends me an SP book, and it's been poorly edited, designed and constructed and I can't take it because I can't sell it. It's even worse when I tell them it needed professional editing, or whatever, and they tell me they paid someone $2,000 to do that already--and it's full of grammatical errors. The distributor can also help you figure your cost/return ratios, help you set a reasonable price, and prevent a whole host of mistakes that SPs often make simply from lack of experience.
(Not all distributors will hold your hand and walk you through this process because it takes a lot of time, and therefore, they will make less money. But many distributors are willing to do this because they know it will make a better product that will sell more copies and hopefully they will get a better return on their time investment on the back end. If a distributor is willing to do this, please, trust them. Listen to their advice. Give them credit for having half a brain and knowing what they are doing. If you don't trust your distributor to guide you, go with a different distributor.)
So anyway, you need to find a distributor as early into the process as you can. When a distributor accepts your book, they then act as your representative with the bookstores--letting them know your book exists, who the customer is, taking and processing orders from the bookstores, shipping, collecting money in your behalf, etc. Their contract should outline what exactly they do, and when and how you will be paid.
The cost for a distributor varies. Some figure it based on the retail price, some on the wholesale. Some lump it all together with the wholesale discount offered to resellers and it is between 55-60% of the retail price of the book. Others will quote it at 25-30% of the wholesale price. (These are approximates and vary between companies, between titles, and depend on the reseller discount, etc. Lots of variables. For example, if they put you in a national chain or on amazon.com, then it might cost you more because the reseller discount is more.)
Some SPs think they can self-distribute for less money than they distributor is asking for. Trust me, you can't. Even if you can get the bookstores to order directly from you, you'll need a way to advertise and market your book, a website, a toll-free number, a merchant account, a garage full of shipping supplies, shipper accounts, and a warm body to fill all those orders. If you're only selling a few copies of your book each week, and you do all the work yourself for free, then maybe you can do it cheaper. But not likely. In fact, highly unlikely.
One other word of caution, if you're using a POD printer, or going with one of the online vanity presses (AuthorHouse, Publish America, etc.) your cost per book is going to be too high for you to sell it through a traditional bookstore at competitive prices, with or without a distributor. To cover all the costs and discounts, you'd have to price your book out of the market. POD is fine if you've got a book with highly specialized information which you plan to sell outside the traditional bookstore (ie: on your own website, at seminars, etc.). But for fiction or generalized non-fiction sold through bookstores, it does not give you the profit margins you need to be successful.