Lowball is the mirror image of the highball: an opening offer set implausibly low to anchor the negotiation downward. The same robust anchoring mechanism applies (Kahneman & Tversky) — the first number reshapes what both parties treat as reasonable, and the first-mover advantage documented by Galinsky can drag the settlement well below true value. A buyer who opens far beneath market, often while cataloguing supposed flaws, is trying to relocate your mental floor before you have re-checked what the thing is actually worth.
As with an aggressive high opening, a genuinely low first offer is not inherently dishonest. A buyer with a real budget constraint, or one who honestly values the item below the asking price and can say why, is bargaining legitimately. The tactic becomes manipulation when the number is chosen for its downward pull rather than its defensibility — a figure with no honest basis, sometimes wrapped in false finality, meant to soften you before you counter.
Because anchoring works even on informed, forewarned people, the defense is again procedural rather than attitudinal. Fix your floor from independent market data before the conversation, treat an extreme low offer as a cue to re-anchor rather than to meet halfway, and keep the discussion tied to objective criteria — comparables, condition, replacement cost — so the opening number never becomes the frame everything else is measured against.