This is very simple and straight forward to do

Go to http://advertise.bingads.microsoft.com/en-au/sign-up

Select Sign Up

There are two ways to sign in to Bing Ads:

1. Use an existing email address (if you have a business email address that you are not already using with Bing Ads). Please refer to Method A below.

2. Create a new email address (if you do not want to use or do not have an existing email address that you use for work, or if you are already using it to sign in to Bing Ads). Please refer to Method B below (skip Method A).

Method A - Use an existing email address. This is the method I use. I use my Gmail Account

NB: If you don't create a campaign straight away, Bing 'teases' you with a voucher to get going, in my case it was $50. Take it!