Apps Script for fetching price information for EVE Online items

script.js

const METRICS = {'AVGBUY': 'buy.weightedAverage', 'MAXBUY': 'buy.max', 'MINBUY': 'buy.min', 'BUYDEV': 'buy.stddev', 'MEDBUY': 'buy.median', 'BUYVOL': 'buy.volume', 'BUYNUM': 'buy.orderCount', 'PERCBUY': 'buy.percentile', 'AVGSELL': 'sell.weightedAverage', 'MAXSELL': 'sell.max', 'MINSELL': 'sell.min', 'SELLDEV': 'sell.stddev', 'MEDSELL': 'sell.median', 'SELLVOL': 'sell.volume', 'SELLNUM': 'sell.orderCount', 'PERCSELL': 'sell.percentile' };
/**
 * Retrieve market information for EVE items
 *
 * @param {number|string} type Name or ID of an item
 * @param {string} metric One of AVGBUY, MAXBUY, MINBUY, BUYDEV, MEDBUY, BUYVOL, BUYNUM, PERCBUY, AVGSELL, MAXSELL, MINSELL, SELLDEV, MEDSELL, SELLVOL, SELLNUM, PERCSELL
 * @param {number} region Optional - Region ID. Uses The Forge (Jita) by default
 * @return The price for the item based on the metric specified
 * @customfunction
 */ 
function getPrice(type="Tritanium", metric="AVGBUY", region=null) {
  var region = (region) ? region : 30000142;

  if (!METRICS.hasOwnProperty(metric)) {
    throw('Invalid metric');
  }
  metric = METRICS[metric]
  var [m1, m2] = metric.split('.')

  var id = (typeof type === 'number') ? type : 0;
  if(typeof type === 'string') {
    var cache = CacheService.getScriptCache();
    id = cache.get(`${type}.id`);
    if (id) {
      console.log(`Got cache hit for ${type}.id: ${id}`);
    } else {
      var response = UrlFetchApp.fetch(`http://www.fuzzwork.co.uk/api/typeid.php?typename=${type}`);
      json = JSON.parse(response.getContentText());

      if (json.typeName == "bad item") {
        throw("Invalid item!");
      }

      id = json.typeID;
      cache.put(`${type}.id`, id, 21600);
      console.log(`Cached ${type}.id: ${id}`);
    }
  }
  var result = cache.get(`${type}.${region}.${m1}.${m2}`)
  if (result) {
    console.log(`Got cache hit for ${type}.${m1}.${m2}: ${result}`);
    return parseFloat(result);
  } else {
    console.log(`Fetching ${m1} ${m2} for ${id} in ${region}...`);
    var url = `https://market.fuzzwork.co.uk/aggregates/?region=${region}&types=${id}`;
    var response = UrlFetchApp.fetch(url);
    var json = JSON.parse(response.getContentText());
    
    var ret = json[id][m1][m2]
    console.log(`Got ${ret}, caching...`)
    cache.put(`${type}.${region}.${m1}.${m2}`, ret, 1800)
    return parseFloat(ret);
  }
}

Simply add this to your sheets' Apps Script, then call getPrice() in a formula