I paid 150 usd for a complete darkroom minus the sink. I had one enlarger, an Omega 2D that's mint plus a Saunders 20x24 easel and a archival print washer. Ton's of other stuff including a bunch of paper. I'd say your offer is more than fair.

Remember that the expired chemicals are a liability. If you take them, you should be compensated for disposing of them properly.