[marglo]

My hobby is entering sweepstakes and I do most of it online so it doesn't cost me usually...now and then I have joined a membership site to get more sweeps but overall it has mostly paid off. Every now and then I win something I can really use so it saves me money too.

Otherwise...not sure these are hobbies..but
I enjoy reading...and I buy most of my books used online and often turn around and sell them again online.
I enjoy traveling...yes, this costs but we do it about as frugally as we can..well, we don't backpack..but as frugally as two older people who like to be comfortable can do it. LOL
We don't spend nearly as much as most people tell me they do when they travel.
I also enjoy forums online such as this one and that doesn't cost me a thing except my time. :-)