Now that you have a full estimate of costs, you can start a thread and optionally a Wiki Entry for the proposed order.
Use previous Bulk Orders as a template, and set rules/conditions for your order. For example see
nILS Bulk Order Terms
Be sure to specify your prices in the currency you are using, due to fluctuations in currency conversions.
It is a good idea to set a deadline for taking orders.
Set up a table for users, either on the thread, or on a Wiki Page, so they can add their Username, Quantity desired, preferred shipping method, etc….
Once you have reached the desired quantity, or the deadline, copy the Table to a Spreadsheet to calculate each member's Cost, and the Total Cost, taking all fees into account.
Request each member's details by email, i.e Username, Desired Quantity, Real Name, Delivery Address, Email Address, Paypal Email Address