The price per 500 mL milk from the 2 packs is $2.50/2 = $<<2.5/2=1.25>>1.25.
This means that for each pack of 500 mL milk, you can save $1.30 - $1.25 = $0.05.
Ten sets of 2 packs mean 10 x 2 = <<10*2=20>>20 packs of 500 mL of milk.
So, your total savings will be $0.05 x 20 = $<<0.05*20=1>>1.
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