exchangeable.net
One adjective stating the core function of any exchange. That efficiency is what makes a genuine dictionary word worth having over a coinage.
Exchangeable carries real financial weight. Exchangeable bonds are a specific instrument, exchangeability is a property of currencies, and in the general sense it describes anything tradeable for something else.
That suits a marketplace, a trading platform, a barter or swap service, a currency product, or a financial instruments business. There’s a plainer consumer reading too, covering returns, swaps and trade-ins, a growing segment as resale becomes mainstream.
Twelve letters, five syllables, no hyphen, standard spelling. The .net reads as a network or exchange, which is literally what the buyer would operate.
Enquiries welcome.