The discount saved when buying from Guitar Center would be $1000 * 15% = $<<1000*15*.01=150>>150.
The total cost when buying from Guitar Center would be $1000 - $150 discount + $100 shipping = $950.
The discount when buying from Sweetwater would be $1000 * 10% = $<<1000*10*.01=100>>100.
The total cost when buying from Sweetwater would be $1000 - $100 discount + $0 shipping = $<<1000-100-0=900>>900.
Thus, Silvia would save $950 - $900 = $<<950-900=50>>50 when buying from Sweetwater.
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