Isabela bought twice as many cucumbers as pencils, meaning she bought 100/2 = <<100/2=50>>50 pencils.
The total cost for purchasing the pencils without the discount is 50*$20 = $<<50*20=1000>>1000
At a 20% discount, Isabela paid 20/100*$1000 = $<<20/100*1000=200>>200 less.
The total amount of money she used to buy the pencils is $1000-$200 = $<<1000-200=800>>800
She also bought the cucumbers at a total cost of $20*100=$<<20*100=2000>>2000
The total cost for the items is $2000+$800= $<<2000+800=2800>>2800
#### 2800