var array=[
  {price:0.112,qty:1},
  {price:0.218,qty:1},
  {price:0.216,qty:1},
  {price:0.321,qty:1},
  {price:0.325,qty:2},
  {price:0.335,qty:2},
  {price:0.536,qty:1}
]

[
  {price:0.32,qty:3},
  {price:0.33,qty:2},
  {price:0.53,qty:1}
]

[
  {price:0.3,qty:5},
  {price:0.5,qty:1}
]

let result = [];
array.forEach(function(a) {
  a.price = a.price.toFixed(1);
  if (result.some(x => x.price === a.price)) {
    result.find(x => x.price === a.price).qty += a.qty;
  } else {
    result.push(a);
  }
});