If you found something useful and would like to give something back, you can contribute by sending a sum of your choosing through Paypal. No need for an account. All you need is a major credit card and Paypal will handle to rest for you.
There are many costs associated with running a Website. Some of them are hosting, trademark registration and the renewal of domain names. With the increasing number of visitors and subscribers, this Website will also require better services to maintain adequate performance.
I am not expecting anything in return, so no need to feel obligated to give back. I do this for my own pleasure. Although this is fun, a bit of help to pay for the costs to run this Website would be awesome. 