Create an arsenal of cleaning products that can clean almost every kind of product (paint, chalk, markers) from every kind of surface (cement, wood, pavement). The best way to conduct a graffiti service is to offer a subscription-like arrangement. Once a month or whatever interval makes sense for your clients, go around to their property and clean off the graffiti. Charge them a monthly or quarterly fee and make it simple for everyone--they don't have to think about graffiti, and you just do your job.
Customer demand for online services may be underestimated if you haven"t researched this. Perhaps, more importantly, you won't understand your online marketplace: the dynamics will be different to traditional channels with different types of customer profile and behaviour, competitors, propositions, and options for marketing communications. There are great tools available from the main digital platforms where we can find out the level of customer demand, we recommend doing a search gap analysis using Google's Keyword planner to see how you are tapping into the intent of searchers to attract them to your site, or see how many people interested in products or services or sector you could reach through Facebook IQ.
There are loads of resources for making money online as an affiliate. You could source products from ClickBank, Commission Junction, Rakuten Marketing, Share-a-Sale, Impact Radius and many others. Plus, many of the larger companies have their own affiliate programs as well. Do your due diligence and find the right company with a relevant product or service to your audience that you can sell as an affiliate.
Because digital marketing has so many options and strategies associated with it, you can get creative and experiment with a variety of marketing tactics on a budget. With digital marketing, you can also use tools like analytics dashboards to monitor the success and ROI of your campaigns more than you could with a traditional promotional content -- such as a billboard or print ad.