For you, I make special deal: NetHaggler [corrected]

Most people (in the United States anyway) are cowed by printed price tags. We see a number stuck on an item and just assume it is the price. But in more cases than people realize, a marked price can be taken as a negotiating position. Some people dislike dickering and choose to ignore this fact. Others (you know who you are) look at financial transactions as a form of sport.

Unfortunately, the Internet is a poor arena for one-on-one shopping combat. When you see a pair of pants you like on Macys.com, you can't ask the salesperson if he or she will let you have it for 10 percent off, or 15 percent if you buy two pair. There's no one to engage with. You can, if you want, bookmark the page and come back to it later to see if the price has gone down. But that's no fun, and it's hit or miss.

But a new site, NetHaggler, has features that exploit the fact that prices for retail goods are rarely, if ever, final. Through three features--tag, nag, and haggle--it lets you track price changes on any object and also ask for discounts.

The service relies on a downloadable browser toolbar. Having to junk up your browser is a downer, but the functionality it provides is good if you shop regularly on its supported stores. To use the service, you drag a selection rectangle around an item you're interested in. At that point, you can "tag" the item and set a pricing alert. You'll get an e-mail if the price falls to where you want it.

You can also make an offer (a "nag") on the item, which will be forwarded to somebody at the store, who will (hopefully) get back to you with a yea or nay on your offer. NetHaggler plans to build a rules platform as well, to automate some of the haggling function. For example, there could be a rule to always grant a discount request up to a certain percentage, except for certain brands, or to allow a greater discount on particular classes of goods or for particular customers. There is no plan to let an online store get offended by your lowball offer and kick you off the site, though.

Finally, there's an interesting, if poorly named, "haggle" function. It's a form of collective purchasing. If you set a haggle price on an item, the system puts your offer into a pool with other offers on the same item, and attempts to bargain for a better price on behalf of everybody who is doing so. The price that gets returned to you (and all hagglers) may be higher or lower than the one you put in. For this feature to work, you have to be bidding on an item that other people also care about, so the haggle function probably won't be much use on obscure products.

NetHaggler is a negotiating engine, not a purchasing system. This means it is unlike Priceline, you are not required to follow through on an offer you make or an acceptance you receive. It's like bargaining with the guy at the car dealership: You can take the best price you get to the store across town. It's dirty pool (and the store could easily retract its offer if you act like a jerk), but it does give you freedom to explore price options on items you're interested in.

NetHaggler only works on about 25 stores right now, but they are mostly major retailers: Macys, Nordstrom, REI, WalMart, etc. The biggest problem is that NetHaggler won't work across stores. If you want to monitor the price of an item that many stores are carrying (say, a digital camera), you'd probably be better off setting a price alert on NexTag than a tag on NetHaggle. But if there's an item you want that's unique to one of the NetHaggler partner stores, the service to nag the store for a better deal could save you some bucks.

If you're in a hurry, you can always pay full retail. But if you have time to wait for a reply, don't be a sucker. There are discounts to be had just for the asking.

Correction: The previous version of this post stated that the stores that NetHaggler works with are willing participants in this project. The founders would like them to be, but they are not, yet. So whether a nag or haggle that you enter into the system will be replied to is a bit of a crap shoot. The price-watching "tag" feature, though, works even without store participation.

See also: PriceProtectr. And all the online coupon sites on the Web.