Okay, i may have stooped to all time low - and may have to delete this post after you've had a good read. Please do not judge me on the following, it's simply here to help you. Cringe.
This post came about after i tweeted about spying on the Topshop item's i wanted to buy in the sale, and Lucy asked how i knew what price's they were going to be reduced to. I work in retail, nothing flash, in-fact my main customers are old ladies - i have acquired several thousand adopted grandmothers during my time working there. Anyway, in the run up to sale, we identify the items that will be going down in the sale prior to it starting, so on the start date we can just gun and ticket. If your really sneaky, you can suss out what items are due to be reduced by looking on the back of the ticket. Not all stores do this mind you, but it's worth knowing.
Each stores have different ways for writing a discreet code, but most of the time its pretty bloody obvious. Note, i bought this top from Topshop yet, i wrote the code on as an example: reduced to £20.
Have fun ;)