Max--I can see two potential paths for you with this project. You could follow along with the advice offered by Directorik (which is all valid, excellent advice!), but it applies more to someone investing enough money to make a marketable feature. Trust me, I know that even a $15k - $25k budget might as well be in the millions for someone who doesn't have it. The other option is to make a "No-Budget" feature with the intent of a) gaining experience at the craft, and b) using the finished product as a way to attract investors for your next effort.
You should know that I am completely new at this as well, so my suggestions should be considered accordingly. What I can tell you is that we made a 15 minute DV horror movie for about $275 (not including camera). The cost breakdown went roughly like this: $25 - wardrobe and misc. supplies, $50 - fake blood, scars, make-up, $50 - blank DV tapes, $150 - pizza, wine, & beer. That's it. Now...there is no way we would consider this movie "commercially marketable," but we did gain some valuable movie-making experience in the process, and more importantly...we had a GREAT time!
If you think that a simpler (and cheaper) start might be a good option for you, here are some ideas to help you out:
1. Get your friends to help you. They are more likely to be willing to help you out without feeling slighted by no pay and cheap food. If you are lucky, they will still be your friends at the end!
2. Craft your story such that it does not require unnecessary expenses. For example, a sci-fi movie would look lousy if you only spend $4.95 for a ray gun. Talk to your friends and family, find out what they can let you borrow for props. Try not to incorporate extravagant items (luxury cars, speedboats, machine guns, etc) unless you KNOW you can borrow them for free. Same can be said about computer visual effects. Unless you already know how to make them happen with post-prod. software, you may want to side-step it for now. (Not to say you shouldn't eventually learn, you just may not want to have your movie rely on a crucial CG scene unless you know it can be done).
3. Do PLENTY of test filming. Blank DV tapes are relatively cheap (and they can be re-used). Directorik was definitely right about lighting. You should know how you want your movie to look, and then shoot the setting over and over again with a variety of lighting options until you find the one that looks right on tape. You can do this on your own, or with a friend to help...but better to have this all worked out and decided BEFORE you bring in the actors.
4. Plan your shots! Work up a full schedule of all the scenes you need to get for your project. Maximize your effeciency by shooting all the scenes needed in setting 1 before breaking down and moving to the new location. Also, remember that makeup, hairstyles, wardrobe, and general appearance need to be kept consistent. Determine if a certain sequence of scenes requires any special appearance considerations and try to shoot all of that in one day so you do not have to go back and re-create "the look."
5. Invest in two cameras. Catching the one perfect take from multiple angles simultaneously can save time. Have a tripod ready for both.
6. Invest in a good quality microphone. Plug it into one of the cameras and capture all dialogue on one tape. When you get into editing, record your audio from the tape into a digital (.wav/.mp3/.aiff) file and lay that file into one of your editor's audio tracks. Reason is--if you are shooting a scene from two angles, you do not want to rely on the audio picked up from the individual cameras because the sounds levels will vary dramatically between them. Drop your movie audio track down to zero and use the copy of the audio from the one camera for all dialogue. If you cannot afford to hire a sound recorder/mixer, start looking now for a good quality sound mixing software program (like Audition) and start practicing. You may not need to do this, though, if you video editing program offers robust sound layers and controls.
That's all I can think of at the moment. Again, please remember that I only started making movies this year, so my experience is limited. These are the things I would suggest for anyone trying to spend less less than $1000 to make a movie. You won't get anything marketable, BUT if you do a great job an investor might be impressed with what you did with such a modest budget. It might get you to that $50,000+ feature project in no time!