Can you help me identify / value 3 pumps, 2 tanks, 1 skimmer?

[Scythanith]

The pumps and the tanks are the only thing really worth their weight. I usually go a $1/gallon (figure out gallons by multiplying width, height, and depth then divide that number by 231). The powerheads would be ~$10 a piece. The skimmer is antique, use it for a flower planter. The plumbing bits with pipe in place you'd be smart just to give away. Good on you for trying to help someone out with reasonable prices.