They do track you by credit card number and address, so it can be hard to get a lot of the deals as they're designed for new clients.

I would love something that compared the cost of these kits to the cost of buying the ingredients at the store, haha. The only times I've used these kits is when I can get a good deal because holy cow are they ever pricey!

Magic eraser is likely to just cause a differently discoloured patch of wall by smoothing out the paint/changing the finish