SHOPPING:
If a shirt is on sale for 50% off, and you have another offer that gives you an "additional 20% off the sale price", does that mean you get a total of 70% off? Not usually. If the shirt was $20, then the SALE price would be $10 and the additional 20% would apply to the SALE price of $10 instead of the original price of $20. This isn't too bad when the sales are nice even percentages, but when it gets more complicated, you can use this calculator to find out the final cost (sales tax not included).