Do many of you edit your price depending on the developer's budget, or do some of you simply stand firm in your pricing?
I've calculated my hourly rate, based on a standard 40h week that I'd need to earn to cover all my monthly expenses (we all know we work way more hours than that, but that doesn't mean you should calculate like that
). If you're doing this fulltime you should do this too.
This way you have a solid reference point for your negotiations. If I come across a project that I'm really hyped about but where the client is on a low budget I might go as low as this "minimun" (but keep rights for re-distribution etc.), which essentially would mean no guaranteed net profit on my end. I would never go lower. Because then I would be the one paying to work on it. And that I simply can't afford. Every client should be able to acknowledge that.
Sometimes, when you're short on work, which can happen at any time, it's hard to turn down projects because of this. But in the long run you're not doing yourself a favor by charging below your "minimum". If you end up to make a returning client out of such a project you'll have a difficult time negotiating for a higher rate next time around.
In short, if the time needed and money offered don't add up and are below what you're worth (and what makes sense) - either don't do it or try to negotiate and make a counter offer what you'd be willing/able to do for the amount offered. If the client really wants you because of your unique style there's a good chance that there's some wiggle room in this regard.
There will always be people who will charge lower (or even work for free). Loosing gigs because of that sucks, but it shouldn't force you to devalue yourself (honestly, I'd rather took up a side job if things would get tough than selling myself short of my minimum for my own psyches sake
).