“Can I write off the expense as a business promotion? If so, how much and how?”---->I guess it depends. In general, you can lawfully deduct your legitimate business promotion activities, i.e., costs of transportation, advertising or the cost of business promotion activities that contain meals and entertainment for your clients.i.e, business lunch ( as you know, you usually can deduct ONLY half of promotion cost that involve both meals and entertainment.). Although many small business owners, as a matter of course, deduct the cost of any meal or entertaiment with a business associate, the government’s rules require that the main purpose of a meal or other form of entertainment be the active conduct of business; the IRS does allow the cost of the meal or entertaimnet to be deducted if it takes place directly before or after a business discussion. The expense has to be ordinary and necessary in the trade, business, or profession. In other words, it must be commonly accepted to have this expense and it must be appropriate in the trade or business. For example, business owners routinely have lunch( entertain) with prospective clients to discuss business with the goal of attracting additional business. This is a common and necessary business expense. The meal/ entertainment costs should qualify for a deduction.