Which Coupon...?

I had two favourites on my Firefox regarding coupons, both from Robert Kaplinsky. If you haven't already, I strongly suggest that you have a look through his lessons.

They're both American, so I favourited them with 'REDESIGN' next to the title, to make them a little more relevant to my pupils. The first of which is a 'Which Chinese Food Coupon Should I Use?'. I took this and used Domino's Pizza:

The assumption is that you know you'll spend £25. The challenge is 'Which coupon should you use?'.
What if you wanted to buy Chicken Wings? Which coupon should you use?


The second is 'Which Michaels Coupon Should I Use?'. I don't know what Michaels is... but I do know Maplin.

To go with this, I have chosen a scenario... You're an aspiring DJ and you need to get some equipment. Maplin offer what you want and you see these two coupons in the local newspaper.
You need two things... a low cost item (Carbon Fibre Record Cleaner at £12.99) and a high cost item (Numark MixTrack Pro II at £179.99). These are things that you might want multiple of (in case of loss, in the low cost item case, and to mix more tracks in the case of the high cost item)...

Here are your different purchase scenarios...
1. You are purchasing three of the lower priced items.
2. You are purchasing two of the lower priced items and one of the higher priced items.
3. You are purchasing one of the lower priced items and two of the higher priced items.
4. You are purchasing three of the higher priced items.

Which coupon do you use? and when?