In a way, negotiation is the polar opposite skill as computer programming. As a programmer, what you do is anything but negotiation. You don't negotiate with PHP to get you code running the way you want it to. You tell it exactly what you want it to do, then PHP does exactly that.
Its upto you to decide whether its worth it. But do understand that the choice is in your hands.
Just biting your tongue a bit and not reacting to first financial offer on the spot, taking a break in communication suggesting that you need to consult (your partner, your plans), reject first offer after this consideration can get you far. Plus being enthusiastic about everything but the money (thoughtful and bit distanced (concerned?) about that, until you get the offer you want to finish with, then enthusiastic as well).
Trying to land the projects you want? You're negotiating. Talking the PM into reducing scope to hit a deadline? Negotiating. Angling for a big promotion? Negotiating.
It's not a bad thing, just human nature.