Really it's worth that in parts even if there is alot more wrong with it than just the fuel pump. If it really is just the fuel pump, that's a steal. While your at it, bring a new fuel filter and multimeter to check the impedance on the injectors, it's just too cheap not to.
A fuel pump is a super easy replacement. Usually when s13's are that cheap it's a head gasket or slung rod.
Things to look out for:
I think I see some rust around the radiator support, never seen rust in that area so it makes me wonder how bad the rest of the car is.
random wire hanging out the relay box under the intake, probably no big deal but makes me wonder if the rest of the wiring is sketch city.
Even if it's a rats nest wiring-rust bucket, it's still a good deal. If he had the sense to advertise the car at that price, we wouldn't be having this conversation as it would have been sold the same day.
just my $0.02