I only have a minute...
$200 is quite low but that is what you agreed to. Don't turn into another whining crybaby photographer now. Tell them that includes publication of your images in the interior of the magazine in one issue only. ....
I agree with everything Robert said except this last item. Your day fee is for the privilege of having your services only. It covers upfront costs and expenses, film, batteries, chewing gum, etc.
But keep your use fees separate and appropriate to the use the magazine will put your images to. For this go to EP as has been suggested previously. Use their calculator as it is a summary of real, already gotten fees, i.e., true existing market value.
Also remember that straight reimbursement of expenses is not enough, except travel expenses. If you are using film, multiply your costs by five. That's the fee you charge per roll ((film price + processing) x 5 = fee per roll). This is the standard way for accounting for your daily expenses of utilities, rents, etc. This formula applies to everything you have to purchase or provide for the job.
Peace! Sidney
