Long story short: people often contact me with ideas for websites/software that they want me to build in exchange for a small amount of money (hundreds of dollars) or small share of equity in the next 'Facebook killer' (typically around 25%). Their contribution can effectivly be summarised as "I'll be the ideas guy".
I'm not the most assertive person in the world and I wonder if people get in touch because they think I'm someone they could easily exploit or because they're just clueless about how much work actually goes into launching a software product or service.
Has anyone else been faced with this situation and how do you handle it?
As to how to deal with it: Take their offer and add to it until you'd be happy to do the work. Tell them you'd be happy to do the work for $X. Don't think of it as being assertive so much as being honest. Remember that you're under no obligation to haggle.