Just to throw an idea out there, but what about a “make an offer” option? I’d see this being mostly relevant for one-off built things rather than kits etc. and it should be optional and allow the seller to make a counter offer.
I know you can do this on ebay but I like Tindie 
Hmm interesting. How many people use that? I honestly stopped buying things of ebay ages ago, so I’m not very familiar with their tricks.
Have you used it?
Meh. Who needs lowballers? You can already set price tiers for volume discounts on Tindie.
Yeah, not a fan of "make me an offer option.