At what price do you guys usually ask for discounts, and is it pretty bad to ask discounts on coins already in the bargain bin?
If I buy one coin, I typically won't try to haggle on the price. If I buy multiple coins, I might try for a volume discount. Another tip that works well in small coin shops is to ask if there is a cash discount. Many such shops don't have large volume payment processing contracts set up and cash payments allow them to save on fees. Some dealers are willing to at least split the difference with their customers who pay cash.
I usually offer/ ask for a price that it be no more than retail pricing, based on eBay, HA, CoinFacts, etc for a really nice coin. NGC / PCGS with CAC, and either nice tone, nice circulated cameo, nice luster, or some other set of "nice" features. These are coins that the seller is at like 125% of retail. I did recently pay a premium on a coin, but my price was still $30 off the asking price of $235. So that was 13% off or so. I usually get 10% off at DLRC. I make offers on eBay all the time, even for items without "make offer". Usually, I get one of the following replies: (1) Counter-offer. (2) Offer Accepted. (3) Offer declined. Rarely, someone is either rude, or worse, totally ignores my email / PM. I really hate that!
Nothing wrong with making an offer on any coin even if in the bargin bin, as Frank mentioned worst they'll say is no.