You should buy the phone with the 50% discount.

If you buy this phone, the cost will be $100. If you buy it through the website, you would first take 25% off:

200-(0.25*200) = 150
jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj
Then you take another 25% off:
150 - (0.25*150) = 112.50.

It is cheaper to take the 50% discount.