My hobbies. Not really a budget buster because I can't buy the stuff for my hobbies because it is too expensive. It's just I've started into the hobbies in the past and left them because of needing new equipment for them.
My first hobby I got into was RC airplane flying. Bought a cheap "beginner" plane and flew it for 2 years. I crashed it hundreds of times and it was really robust. It finally died on me with a harsh nosedive into the ground. I still am interested in the hobby, but need to move beyond the cheapie beginner plane and that will cost several hundred which I don't have. Hobby is sitting on hold.
Next, photography. I needed a new camera and when researching models online, I ended up reading more about photography than cameras. Thus, I skipped the pocket cam idea and went with a fuller body superzoom with full manual function. I learned what I could and outgrew the camera quite rapidly. Unfortunately, I need to upgrade myself to a DSLR, but they are just too darn expensive. A "beginner" DSLR isn't going to get me much more than I already have, along with I know what I want and a "beginner" isn't going to give it too me. So, I'd be looking into about $1000 for my Nikon D90 and lenses that I want. I don't have $500 to spend on my RC hobby, I sure don't have $1000 to spend on a camera. Hobby is sitting on hold.
My current hobby, guitar. Wifey bought me a cheapie acoustic guitar way back in 2005. I've always been interested in guitar, and electric is what I'm interested in, not acoustic. I played around with that acoustic for 5 years but didn't learn anything. Wifey went back to work after the youngest started school and wanted to have a nice Christmas. We've gone 9 years of not doing much for Christmas. So, she splurged on me and bought me my electric guitar. Spent $300 on the guitar and amp. A $200 electric guitar is still a cheapie, but it turned out to be a dang nice guitar. I love it. I've learned more the past 6 months since Christmas than I had in 5 years with the acoustic.
The nice thing about this guitar I have is, it's an inexpensive guitar and not just a cheapie. It is very nice and I absolutely love it. I'm not looking for anything more or better or upgraded like I am for the other 2 hobbies. You can get into thousands and thousands worth of equipment with the guitar, but I am perfectly happy with the one I have. In the future, I'm sure I'll get into more stuff with it, I'll be "needing" some effects pedals and such, but now we both work, we are going to Disneyworld which 15 months ago we were wondering how to pay the two housepayments that were due and never even thought we'd be able to go on vacation. Heck, we have a 9 and 6 year old, have been married for 13 years, and this Disney trip this year will be our honeymoon.