Thought I'd take a detour and give you a short list of things I've tried, in an attempt to save money, that were NOT worth the effort.
Garbage bags... Store brand sometimes are ok, however the 'super generic' roll-type bags or value boxed bags are not worth the money. They tear and do not hold much and you will be determined to finish the bag/box before replacing them, guaranteeing about a months worth of frustration.
Toilet paper.... if you have a large family like mine, the 1000 sheet rolls are a must. Name brands do not matter here as the store brand usually has a 1000 sheet roll or set of rolls. They last 2-3 times longer than the other rolls. No, they are not as stiff as 'parochial school brown sandpaper' toilet tissue either. Don't even think about trying the $1.00 four packs. They evaporate when no one's looking.
Buy one, get 2 free deals if they tripled the price just in time for the sale. Nuff said.
Cheap digital cameras.... if you have a semi-serious photographer in the family, the quality will really suffer. Better to get a midline model on sale pre holiday or post holiday. We found a nice waterproof digital camcorder for half the price of our old vhs camcorder this way.
Super Saver shipping on Amazon... really check on each item if you are actually saving shipping. Most raise the base price to cover this. This works best on multiple heavy or larger items.
Alternative/cheaper charger cords for Nooks, etc. Though these technically work, they usually charge much slower and do not fully fit the ports. What DOES work is getting the warranty to cover the Nook, etc and getting cords that actually fit replaced for free if/when they do break. We've replaced 3 cords this way on the same warranty.
Cheap vacuums.... I got a Kirby once many years ago, and my husband still teases me about it. It didn't last a lifetime like I expected- only about 10 years, but I replaced the cheaper ones almost every year prior to this. Since moving away from the local dealer/repair shop, I've had to revert to a canister one and I've already clogged it because of our heavy use. Again, warranty to the rescue. Rule of thumb: Over $50, warranty it!
Cheap sheets... like bargain basement cheap... they are scratchy. If you are not picky, they do work, but they do not last and it will take years to become soft and only once they are threadbare. Flea markets sometimes have the nicer ones in a higher thread count that are cheaper than main stores, but be aware they may be seconds and not fit correctly.
Cheap sneakers... I vacillate on this one because I have 4 kids who grow out of shoes faster than they change grades. We did the walmart thing every year, but they wouldn't last 3 months before they would come apart BEFORE they grew out of them. Very frustrating. On the other hand, mine last forever... must be a kid thing. But for them and me, the nicer brands are better on your feet and last much longer. We have outlets nearby that we can get the second pair half off, so we shop the clearance racks and get 2 nice pairs for not a lot more than we would for two at wallyworld.
Cheap tax preparers... got an instant $50 for walking in to a particular office last year. End result? Our taxes were messed up for months and we owed a surprise $700 in August. Best bet, get word of mouth referrals, and if you cannot afford a tax person at all, look into the program Tax Slayer or similar programs. We did this one year when our taxes were simpler and it was easy, fast, and cheap. Otherwise, some communities offer free volunteer tax preparers to middle and low income families.
I'm sure some have missed my list, so I will do another one in the future. Hope you enjoyed and feel free to post your bad experiences- we can all learn and save our money!