As far as insurance/return policies, we obviously have them in place for people who come into the physical stores, but we need to figure out what they'll be for online. Since we sell on eBay as well as Amazon, we're more than familiar with what works and what doesn't work in terms on online dispute resolution. That is one of the big advantages we have over someplace like eBay - when they get in the middle of a transaction, they never have actually handled the items in question. Were the pictures accurate that the seller took? Was the box trashed by the shipper? We're the ones who take all the pictures, we write the descriptions, we note the condition details, etc. I would say we err on the side of showing even minor things, because we would rather have the buyer be pleasantly surprised then slightly disappointed.
On a couple of the more technical things we've sold in the past to people online, they've called and walked someone at our store through the process of testing an item to ensure it's in working order - if you're familiar with datacenter stuff, think of it like remote hands. While one of our employees might not be able to flip on an oscilloscope and tell you if it's working or calibrated, if you're familiar with the item you can generally determine if it's working or not. We test everything to the best of our ability, but the shear breadth of things we carry means that we can't exhaustively test everything.
So, to your specific question - I suspect our return policy will be something mainstream like 30 days. Refunds would be in either Bitcoins or if the person wanted, they could put it on a giftcard - but not USD (otherwise I suspect we could run into some legal issues).
As far as insurance (I'm assuming you mean shipping insurance), we don't normally do it since we haven't found a big need for it - but if it was something that people felt was important, then we could certainly do it - it just costs more in terms of shipping.
Thanks for the in-depth responses, . I'm definitely looking forward to seeing how this pans out!