In the case of eBay stuff, you have to be careful alright, but I don't see what's wrong with asking a direct question. If you get a direct answer, you know where you stand. If you don't, take your money elsewhere. It's not the bargain basement it used to be - things are cheap for a reason. If they don't say "fully tested and working," send them a mail asking "Does it work?"
For a store like AmigaKit it's usually much better, but still, they've always been quick to reply to any questions I send them regarding technical details of their products, and overall quite helpful in that respect.
Before I buy anything on eBay that's what I do, it pays to ask specific questions about the item condition, postage, packaging etc...
That way if anything goes wrong then you're virtualy guaranteed to get a full refund from ebay if the seller has provided you in an eBay message the condition of the item and it doesn't match when you receive it, even if it does say no returns or refunds in the listing...
On the postage side I've bought a lot of stuff from the USA recently and the longest anything has taken is 11 days, even had stuff from China arrive with 6 days...
