Splitting the Money
Collaborations are often arranged on a fifty-fifty basis, but an even split certainly is not required and may not be appropriate in some situations, depending on how the work and responsibility are divided. Your best strategy is to determine money-sharing arrangements on a case-by-case basis.
Valuing Each Other's Contribution
There may be instances in which it makes sense for you to ask for more or less than a straight split. If your coauthor is going to supply all the research and information, and your responsibility is to organize and write the proposal or manuscript, that's a fairly even distribution of labor; and a fifty-fifty split is appropriate. However, if you have to supplement your coauthor's contribution with your own research, that might be worth another 10 percent (or more) of the proceeds from the book, depending on how much extra work is involved.
Alternatively, you might agree to a smaller cut if your workload is significantly lighter than your coauthor's. For instance, your collaborator already might have done the bulk of the research and writing, and your contribution is a matter of rewriting here and there, perhaps with a little reorganizing to make the material flow better. In this situation, your share of the work will take less time and effort, so taking a smaller share of the revenue is fitting.
Assigning a monetary value to the work, expertise, and time each of you brings to a project can be tricky; you don't want to undervalue either your contribution or your coauthor's. The most important thing is that you and your collaborator feel that the money-sharing arrangement you make is fair to both of you.
The issue of writers charging upfront fees to work on book proposals is a controversial one. Although legitimate writers sometimes charge these fees, unscrupulous practitioners have been known to demand unreasonable upfront payments from would-be collaborators and then fail to deliver a salable proposal or manuscript. As a result, many people tend to look askance at writers who require payment before a publishing contract is offered.
Don't expect a publisher to pay for any specific expenses you incur while researching or writing your book. You (or your agent) might be able to negotiate a larger advance if there are extraordinary expenses attached to your work, but that is only a “maybe.” For the most part, publishers will view your expenses as part of your own investment in the work.
Certainly, there are legitimate arguments to support reasonable upfront fees. Creating a marketable book proposal or manuscript takes time and creative energy, and a writer who spends his time and energy on your proposal can't spend that same time and energy on another project. Asking for modest compensation for the use of those assets is both licit and appropriate.
On the other hand, exorbitant upfront fees should make you wary. If a writer wants, say, $10,000 to prepare your proposal or manuscript before you have a publishing contract, ask if the fee will be deducted from her share of the advance if you sell the book. If not, consider looking for another collaborator.
Usually, collaborators are responsible for their own expenses. If you have to mail something to your coauthor, you foot the bill for it; if he has to ship something to you overnight, he pays for it. The same applies to all the normal costs of doing business — long-distance phone calls, copying, and so on. In a normal collaborative work, these costs will be minimal, and the easiest way to address them is for each collaborator to assume responsibility for his own expenses.
However, there may be instances when extraordinary expenses can be expected, and this can be a factor when it comes to deciding how to split proceeds from a book sale. For example, if you have to travel to South America for a month to do research for your project, you might want to take that expense into account when negotiating the split. You may decide to absorb those costs, or you might be able to arrange for reimbursement out of the publisher's advance if you sell the book.