No matter what you do to prevent it, it is bound to happen: unwanted or repeat gifts. Rather than keeping that extra bread maker, there are other options! The best option, of course, is to return the gift for cash; however, you will likely need the receipt. Even if you are not able to get ahold of it, many stores will still give you store credit. Just remember to be nice and do not be afraid to talk to a manager if the first person you talk to does not think they can help you. Also, do not forget to take note of a store's return policy before registering - this might make things easier to begin with!
However, without a receipt, you may not know where to return the gift in the first place! New apps, like Pounce, can be used for product recognition, telling you where it is sold for returns. Even if the product was not purchased from that store, many stores are lenient on accepting products that they keep in stock.
Also, consider selling the gift. Whether on Craigslist or eBay, you might not get the full market value, but you will get some extra cash in your pocket to go towards something you do need.
If all else fails, you can always donate your gift. Blessing someone else is always a good option!