He found 12 and his grandparents gave him three times that amount so he got 12*3 = <<12*3=36>>36 cans from his grandparents
All total he collected 12 cans, the 36 from his grandparents, 46 from the neighbor and 250 from his dad for a total of 12+36+46+250 = <<12+36+46+250=344>>344 cans
Each can is worth $0.25 so .25*344 = $<<.25*344=86.00>>86.00
He agreed to put half of the $86 earned into savings so he will save 86/2=$<<86/2=43.00>>43.00
#### 43