Microsoft Ads $100 Free Ads Credit Promo Coupon Code on Spending $25 Only. You will earn free $100 bing search engine advertising credit when you spend $25 in Microsoft Ads. With Microsoft Ads, your business can connect with millions of searchers on the Bing Network. Microsoft Ads will charge only when customers click your ad. No click, no charge. You can promote your business based on different geographic regions, times or days of the week, and even demographics.