If I may, let me give you some more information. Just because some greedy jerk is trying to sell a round of 38 Colt New Police for $5 a pop on Gunbroker, it doesn't mean that is the going rate. Many sellers list items on Gunbroker for ridiculous prices. Gunbroker's seller's listing fees only charge the sellers if the items sell. They can keep automatically re-listing the items (guns, ammo, etc.) for as long as they want, on the chance they will get a sucker eventually. There is no incentive for some of the sellers to list items at a fair price like they would if they paid Gunbroker for every listing, as most auction sites do.
Only an idiot would pay $5.00 for 1 round of 38 Colt New Police. It is just not that rare a type of ammunition.
If you want to see how much an item or items are selling for, check the closed auctions on Gunbroker, not the current listings. Examples:
1) A 1953 or early 1954 S&W Chiefs Special Airweight with the aluminum cylinder (only about 3,000 were made with aluminum cylinders before S&W switched to steel cylinders.) It's in well used condition with a lot of wear. This bozo has had this gun listed for almost 2 years at a minimum of $500. Every snubby collector on the S&W Forum (membership about 125,00 people) has seen this gun by now and nobody wants it at that price. He's hoping for a sucker to come along and he has no incentive to price the gun fairly as long as Gunbroker lets him re-list until it sells. I see now he has changed his ad to show a Buy It Now of $1400 (that's new). If this gun was worth it, with all of the S&W snubby collectors around it would have sold. He probably noticed somebody is selling a similar example on Guns International for about $1400, but that one is near mint.
Smith & Wesson J frame Airweight Chiefs Special : Revolvers at GunBroker.com
2) A gent (could be a member here, I don't know) has a box of 38 Super Police he's trying to sell at a starting bid of $30. He had a few bids one auction up to about $50 but it didn't reach the hidden reserve. This is not common ammo, but it's obvious the box is torn and missing at least half the flap pictured at the right in the photo. I contacted him about the box condition, and asked if the box was missing a flap section or was torn. He replied something like "well, nothing important was torn." He never mentions this in his auction, nor has he bothered to take a few more pictures to show the damage. The condition of the box is as important as the condition of the ammo, as is if the box is full or partially full. I wanted this ammo, but since I couldn't induce the seller to expand on the box damage with some revealing pictures or edit his text to mention the box damage I passed. He's been trying to sell it for quite a while.
Western 38 Special SUPER POLICE Ammunition Box : Vintage Ammo at GunBroker.com
A box in v.g. or better condition of 38 Colt 38 New Police is worth about $40-$60, tops. It's just not a $100 + item.
I was going to put some pictures in this thread to show you 32 New Police, 38 New Police, 38 Special, and 380 Auto ammo and boxes I bought at local shows and on the internet, all for $50 or less, all in v.g. or better condition, but it seems like ImageShack photo hosting has either dropped off the net or is down for technical reasons the past two days. The box of 1940s vintage Remington 38 Special was pristine, shrunk wrapped in plastic for years, and cost me $25. The dealer specializes in ammo, and after he sold it to me, mentioned he mis-marked the box, and it should have been $35.00
HTH,
Mike
* I should have mentioned that if the ammo is from the 19th century up to the beginning of the 1940s (pre WWII commercial ammo) and it's a full box with ammo and box in v.g. or better condition, the values would be higher whether the ammo is rare, just scarce, or fairly common and would be priced accordingly.
All my collector ammo is from the early 1940s through the late 1950s to go with the era of Colt revolvers and semi autos I have accumulated. It's mostly Remington with a smattering of WW mixed in. I'm betting the ammo your friend got is post war 1950s-1960s Winchester like the box Wyatt has pictured.