"Stick to the List" Challenge

My full intention today was to stick to the list when I was at the store.  I put the list on my cell phone so I wouldn't forget it at home.  Here was my list:
Scrapbook 8x8 size and paper to go inside (part of my father's day present)
garden shears (the bushes are needing trimming)
baby decorations (for a friends shower)
Xbox 360 live 12 month membership
tennis balls if under $2 ( for t-ball practice)

So I get to the store and start with the Xbox membership.  Online they are $46.94 at Walmart, then it said that I could buy the same thing at the store for $48.94, so I was thinking I would like it sooner than later.  They said it was in stock, but when I got to the store they only had an empty space for a $59.94 card, which it is sold for $59.99 online.  I was disappointed, but right next to the display was an EA Sports Active 2 game.  It was on clearance for $25 from $59.94.  I couldn't pass it up and therefor veered from my list.

So I walked out of the store with no Xbox membership, but a new game.  Walmart also only has 12x12 scrapbook supplies so I wasn't able to get those.  I plan on going to Micheal's and using a 50% coupon, plus they have scrapbook paper on sale too.

I also wrote down some items for future shopping list:
tomato plant $1.65
pepper plant $1.15
plastic pitcher $2.00

So here is a challenge:

I'm starting a challenge for 30 days.  I want to make a list before I go to the store and stick to it.  I will not be able to add items when I'm in the parking lot.  If I find something I think I need, I will write it down and consider it for the next trip.  It is especially hard for me to stick to the list when I have my kids with me, but I think if I get them involved in helping me shop with the list it will help.  I sometimes tell them if they see something they want I will put it on their Christmas or birthday list.  It's not saying no so they seem to like the idea.  At the end of the 30 days I"m going to compare my figures to last month to see how much money I can save by doing this.

So far today I would call this a failure. -$25 in the hole.