The best way to purchase 0patch licenses (as many as you need) is to create an account in 0patch Central, login, and press the BUY PRO button on the Account page. (Note that the Quantity field looks like a dropdown-only, but you can enter any number there.) Successfully purchased licenses will appear under the LICENSES tab, and issued invoices under the INVOICES tab.
Supported payment methods on the purchase form are credit card and PayPal.
For quantities of 100 licenses or more, we can issue you a quote in form of a proforma invoice so you can make a wire payment. If you wish that, please contact firstname.lastname@example.org and provide the full address of your company, plus your VAT ID if based in EU.
Note that 0patch licenses are subscription-based and have to be renewed after they expire in order to continue having PRO micropatches applied.