It all depends on what condition the system, games, etc. are in. If the system, box, and controllers are all in good shape, I could see paying $20-30 for the hardware alone. Does it have an Expansion Pak installed? If so, that's an extra $5 value.
The sports game is worthless, but I could see paying as much as $5 each for the other titles if they're in decent condition (carts aren't all scratched up, written on with marker pens, etc.).
The N64 hardware and software held their value back in the day but have dropped significantly in value since then. Unless you just really, really have to own an N64, don't feel that you need to pay a premium to get one.
Heck, if you lived anywhere near me, I'd be happy to give you a worn but working N64 system free of charge.