You can use existing ad campaigns and creatives to create your own advertisement. For example, you are an owner of a small online music school and have no idea where to find the budget for your marketing campaigns. You can just take a look at how your fellow online schools from other countries ran guerrilla marketing campaigns and what results they got. Find an example that suits you the best and adapt it to your own business.
All the examples that we've collected in our library have great ROI, meaning that low budget campaigns gained great results, more customers and sales.