Buy bottled water in bulk at Costco or Sam's Club and sell it for a dollar where there are a ton of people: parks, festivals, concerts, etc. People are crazy for bottled water and this is a little summertime gig that can bring in more money than you'd think on a hot sunny afternoon. Here's a bonus tip: give some of your proceeds to a charity you care about or that you know will resonate with people. In doing so, you're bottled water business isn't all about your profit. You're helping better our world and also provide a thirsty person some water to drink.
Whether you have a website or are still dreaming up ideas for a blog, you can also look into affiliate marketing. With affiliate marketing, you partner with brands and businesses within the content of your website. If you mention a product or service, you link to that produce or service using a unique affiliate code you received when you signed up for that particular affiliate program. From there, you’ll make money any time someone buys a product or service through your link.