Interesting dilemma you have there. As a photographer, I must admit you're in a bit of a pickle. But alas! There is hope!
In a day and age where digital cameras are a dime a dozen, I am going to make what may be considered, a brazen suggestion. Though you might be able to find yourself a used digital camera online (ebay?) for under 40$, more than likely you will be purchasing something obsolete, damaged, or with poor image quality.
My suggestion, is to pick up a Kodak or Fujifilm DISPOSABLE camera (Oh yeah, I went there). For occasional use, disposable cameras offer great flexibility, decent image quality, and more importantly, are cheap. Why buy a used low-quality digital camera when you can get better results from something you can repurchase whenever the need arises? Plus, being on film, your image quality will be far superior to using a digital camera with a 3-5MP (Tiny) sensor and horrible optics.
Anyways, I use a Canon 5d Mark II and a Nikon D300s with various lenses, CS4, stands, lights, filters, extenders, etc... I'd still go the film route for occasional shots if I were on such a budget.
Hope that helps.