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eBay - Baby gear retailers like to use eBay for clearing their overstock, so this is a wonderful place to find good buys on strollers, and there are tons of different models to choose from. However, make sure you know what you're buying before placing any bids, or you may end up with something totally different than what you expected.
Craigslist - Great deals on strollers can also be found here, but again, make sure to take your time and examine carefully what you're purchasing.
Online discounters - Discounts abound on these websites for the previous year's strollers. Use search terms such as "discount baby strollers" or "stroller discounts" to find them. And don't worry about not having the newest stroller on the block, since models don't change that much from one year to the next. The money you will have saved will be well worth it.
Online factory Sales - Some stroller manufacturers, such as Peg Perego (www.pegperego.com), sometimes have factory sales online in order to get rid of overstock or models that might have a few imperfections. Check out their websites to find out what deals they have available.
That said, during all your bargain-hunting, don't forget to keep safety in mind. Thousands of stroller-related injuries occur in children every year in the United States. Make sure to choose a stroller that has the Juvenile Product Manufacturers Association (JPMA) Certification seal, which means the stroller has undergone rigorous testing before it is sold in the marketplace. And even if the stroller you choose has this seal, go and check the websites of the Consumer Product Safety Commission (CPSC) and the JPMA to make sure it hasn't been subject to a recall.
If at all possible, once you've decided which stroller you want to purchase, go to a store and try it out, then buy it online for a lot less. Shipping can be expensive, so see if you can get an online coupon (a special discount) from websites such as EdealsEtc.com, FatWallet.com or CouponSnapshot.com. The money you save doing this can then be used for something else.