BidWix – one-shot price agreement using secret max/min
Game theory price negotiator using geometric mean, but solves a narrow niche with no revenue model.

Sealed-bid negotiation tool preventing anchoring bias with no signup required.
Buyers, sellers, and negotiators needing fair price discovery
Procurement auction tools · Escrow.com
Game theory price negotiator using geometric mean, but solves a narrow niche with no revenue model.
Game theory negotiation tool that splits the surplus using geometric mean.
eBay and Poshmark already have offer buttons, so the "first truly offer-based" claim is dubious.
Gumroad alternative selling URLs directly with half the fees and no uploads.
Reverse-pricing calculator fixes the margin leak problem for marketplace sellers.
Seven GTM validation tools beat single-purpose competitors but methodology is unproven.