curl --request POST \
  --url https://api.hubapi.com/crm-objects/v1/objects/line_items

[
  {
    "name": "hs_product_id",
    "value": "1642736"
  },
  {
    "name": "quantity",
    "value": "50"
  },
  {
    "name": "price",
    "value": "9.50"
  },
  {
    "name": "name",
    "value": "A custom name for the product for this line item. Discounting 5% on bulk purchase."
  },
  {
    "versions": [
      {
        "name": "amount",
        "value": "475.00",
        "timestamp": 0,
        "sourceId": "LineItemAmountCalculator",
        "source": "CALCULATED",
        "sourceVid": []
      }
    ],
    "value": "475.00",
    "timestamp": 0,
    "source": "CALCULATED",
    "sourceId": "LineItemAmountCalculator"
  },
  {
    "versions": [
      {
        "name": "quantity",
        "value": "50",
        "timestamp": 1525368534412,
        "source": "API",
        "sourceVid": []
      }
    ],
    "value": "50",
    "timestamp": 1525368534412,
    "source": "API",
    "sourceId": null
  },
  {
    "versions": [
      {
        "name": "hs_lastmodifieddate",
        "value": "0",
        "timestamp": 0,
        "source": "CALCULATED",
        "sourceVid": []
      }
    ],
    "value": "0",
    "timestamp": 0,
    "source": "CALCULATED",
    "sourceId": null
  },
  {
    "versions": [
      {
        "name": "price",
        "value": "9.50",
        "timestamp": 1525368534412,
        "source": "API",
        "sourceVid": []
      }
    ],
    "value": "9.50",
    "timestamp": 1525368534412,
    "source": "API",
    "sourceId": null
  },
  {
    "versions": [
      {
        "name": "name",
        "value": "A custom name for the product for this line item. Discounting 5% on bulk purchase.",
        "timestamp": 1525368534412,
        "source": "API",
        "sourceVid": []
      }
    ],
    "value": "A custom name for the product for this line item. Discounting 5% on bulk purchase.",
    "timestamp": 1525368534412,
    "source": "API",
    "sourceId": null
  },
  {
    "versions": [
      {
        "name": "createdate",
        "value": "0",
        "timestamp": 0,
        "source": "API",
        "sourceVid": []
      }
    ],
    "value": "0",
    "timestamp": 0,
    "source": "API",
    "sourceId": null
  },
  {
    "versions": [
      {
        "name": "description",
        "value": "This product has an updated description and price.",
        "timestamp": 1525287810508,
        "source": "API",
        "sourceVid": []
      }
    ],
    "value": "This product has an updated description and price.",
    "timestamp": 1525287810508,
    "source": "API",
    "sourceId": null
  },
  {
    "versions": [
      {
        "name": "hs_product_id",
        "value": "1642736",
        "timestamp": 1525368534412,
        "source": "API",
        "sourceVid": []
      }
    ],
    "value": "1642736",
    "timestamp": 1525368534412,
    "source": "API",
    "sourceId": null
  }
]