The total cost of the four T-shirts is 4 x $20 = $<<4*20=80>>80.
Three pairs of pants cost 3 x $80 = $<<3*80=240>>240.
Two pairs of shoes cost 2 x $150 = $<<2*150=300>>300.
The total amount of all the items is $80 + $240 + $300 = $<<80+240+300=620>>620.
Thus, Eugene will get a discount of 10/100 x $620 = $62. Therefore, Eugene will have to pay $620 - $62 = $<<620-62=558>>558.
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