To make some quick cash, you can sell banner space in the unused areas of your website. The amount of payment you can get for a banner highly depends on traffic of your website. For this you will get paid up front and the contracts are usually made for 30 days.
To find advertisers you can join different ad networks such as BuySellAds, or you can do some self-promotion on your own website, and expect to be contacted by your visitors who want to buy your ad space.
This strategy can bring you quick money, but it can be tedious if advertisers don’t renew their contract and you have to always find new ones.
