How much cheaper do bike shops purchase products? can someone give me a few examples?

im not lookin for deals im just wondering

That depends. A lot on parts and not that much by comparison on bikes. Suppliers often offer close-out deals on tires, tubes, etc. to bike shops. But in general you, the customer, pay about double on those accessories. And even though bikes are more costly to you, it's rare if the retailer ever makes more than 40% on a bike. Use this info wisely. It is always a good idea to develope a relationship with your local bike shop rather than make them feel like it's a pain in the rear to deal with the price chopper just looking for a deal. Bike shops house good folks usually looking to support their own habits. Good luck with this one.

Han is right on. Accessories are usually priced at a 50% margin. Bikes can go anywhere from 20 to 40% margin. That being said, the shop needs to make a profit to stay in existance. Usually, overhead is about 20%, so, you can see why a shop can't give great deals on bikes and why they'll often throw discounts on accessories.
If you're just looking for a deal, the LBS is probably not your best route for that. The LBS is a community member that is there to help promote the love of cycling; hence, growing relationships and service. They're usually filled with people nuts about cycling (I used to own one; so I'm speaking first-hand here) who'll freely share their enthusiasm with just about anyone - even the guy/gal who just wants to kick tires or save a few bucks.
Good luck to ya!