You can actually make the hobby incredibly frustrating and start to turn it into a job rather than something you do for fun. Sure, you spend alot of time changing the water, testing it, feeding them and making sure you are providing the perfect environment. The only thing that I have found expensive about this hobby is the initial start up cost. I have a great pet store that allows me to 'trade in' fish, per say, so it rarely costs too awful much to stock my tank if something tells me I want to try something else. That way the fish get a good home, and it allows me to 'change things up'. If you want to make your hobby more interesting, try something different. I started with oscars, and then went to barbs and eels, then loaches, then blood parrots, then cichlids, then angelfish, and now I'm messing around with tetras and bichirs. This is a great hobby with ENDLESS possibilities. It's one of the better hobbies that I have had that my wife actually enjoys (most of the time!

). I do admit that I am tired some nights and almost dread having to get up to change the water, or feed the fish. But I muster up all the energy that I can and take care of it. My fish are more like my pets than a decoration. It means alot to me to make sure they have a nice environment to live in. Seeing my fish happy and active makes me want to keep fish even more.
I started with a 10 gallon and a betta or two. My wife and I had talked about getting an aquarium, a small one mind you, probably 2.5 gallons max. I decided I wanted to open our options a little bit, so I went with the 10 gallon. A little ways down the road I now have a small 15 gallon pond, working on building a 20-30,000 gallon pond, a 40 gallon breeder, and still have my 10 gallon. I'm wanting to get a 6 to 8 foot tank in the future, but again, thats way down the road. I admit, this hobby isn't for everyone, and one thing that it does take to make this hobby successful is time.
One thing that has really kept me in this hobby and made me a better fishkeeper are forums like this one and helpful members and LFS owners, as well as local aquarium keepers and breeders in my area. There are different hobbies for everyone, so if you aren't enjoying this one, find something that you do enjoy. Might as well find something that you can have fun at than try to keep something going that makes you miserable.
Good luck in finding a hobby!