My sewing usually saves money, assuming I would buy the things I make. All of DD's holiday and birthday clothes have been handmade, and I know they've been cheaper than their store-bought counterparts.
Knitting and crocheting....that costs me money. I've sold a few items here and there, but mostly I spend money on that hobby. It's fun, and I'm not planning on giving it up any time soon.
Gardening....I've gotten better about not spending so much on plants. In fact, I rarely go to the nursery anymore. But funnily enough, I've been thinking baout it a lot lately.
Internet/web site - that brings in money and other perks but takes a lot of my time, and that is a cost that sometimes frustrates me. On the plus side, I get a lot of free books to read, which feeds one of my other hobbies. I use the library and borrow books a lot more now than I used to, so my reading doesn't cost me all that much. I don't feel bad spending money on books, however.
I guess that's about it for me hobbies.