Update: Some offers mentioned below are no longer available. View the current offers here.Multiple airline shopping portals have launched new “Holiday at Home” bonus miles promotions. But, no matter the name, the important part is that you can score up to 6x the typical number of miles through various shopping portals for a limited time.Not sure what a shopping portal is? It’s a retail outlet that lets you make the most of each dollar you spend by clicking through an online portal to earn extra miles on purchases. Shopping portals sometimes offer cashback on your spend, while other times you can earn points, miles or other rewards instead. Sometimes, you can even double, triple or quadruple-dip on purchases or dining out.Let’s take a look at some of these great offers, and then we will show you how to maximize these offers by double- or triple-dipping on your purchase.1-800-FLOWERSPortalCurrent RateStandard RateValuation Per MileReturn on SpendingUnited MileagePlus15x1.421%American Airlines AAdvantage10x1.414%Alaska Mileage Plan7x1.812.6%Southwest Rapid Rewards7x1.510.5%British Airways6x1.59%GrouponPortalCurrent RateStandard RateValuation Per MileReturn on SpendingAlaska Mileage Plan10x3x1.818%Chase Ultimate Rewards4x2.08%British Airways5x1.57.5%Southwest Rapid Rewards3x1.54.5%American Airlines AAdvantage3x1.44.2%Under ArmorPortalCurrent RateStandard RateValuation Per MileReturn on SpendingChase Ultimate Rewards8x2.016%American Airlines AAdvantage7x5x1.49.8%Alaska Mileage Plan5x4x1.89%Southwest Rapid Rewards5x4x1.57.5%British Airways5x1.57.5%Delta SkyMiles5x3x1.26%United MileagePlus4x3x1.45.6%eBagsPortalCurrent RateStandard RateValuation Per MileReturn on SpendingBritish Airways10x1.515%Chase Ultimate Rewards7x2.014%Alaska Mileage Plan5x1.89%Southwest Rapid Rewards5x1.57.5%American Airlines AAdvantage5x1.47%Macy’sPortalCurrent RateStandard RateValuation Per MileReturn on SpendingChase Ultimate Rewards6x2.012%British Airways7x3x1.510.5%Alaska Mileage Plan4x2x1.87.2%American Airlines AAdvantage5x3x1.47%Southwest Rapid Rewards4x2x1.56%Neiman MarcusPortalCurrent RateStandard RateValuation Per MileReturn on SpendingChase Ultimate Rewards6x2.012%British Airways6x1.59%American Airlines AAdvantage6x3x1.48.4%Alaska Mileage Plan4x2x1.87.2%Southwest Rapid Rewards4x2x1.56%BelkPortalCurrent RateStandard RateValuation Per MileReturn on SpendingAmerican Airlines AAdvantage6x2x1.48.4%United MileagePlus6x1x1.48.4%Chase Ultimate Rewards4x2.08%Alaska Mileage Plan4x1x1.87.2%British Airways4x1.56%Maximizing Your PurchaseWhile 15x miles is already an excellent return, you’ll earn even more miles and points by using the right credit card. And, sometimes you can even triple-dip on purchases by purchasing a gift card through United’s MileagePlusX app and then using that gift card after clicking through the shopping portal links. If you don’t mind stopping by a Staples or other office supply store, you can earn 5x Ultimate Rewards by purchasing a gift card with the Chase Ink Business Cash Credit Card and then using that gift card to buy the products you want online.Let’s walk through how this could work. Say you plan to spend $100 on Under Armor purchases. You’ll earn 3x miles (before a 25% bonus if you have a United cobranded credit card) by buying a $100 gift card through the United MileagePlus X app. By using the right credit card, you’ll earn bonus points on the purchase of the gift card. Then, earn even more miles by clicking through the shopping portal link and using that gift card to make your purchase.Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.Dip 1: 300 United miles through MileagePlus X (3x not including potential 25% bonus)Dip 2: 150 Chase Ultimate Rewards points for the purchase of the e-gift card with your credit card (1.5% with Chase Freedom Unlimited)Dip 3: 800 Chase Ultimate Rewards points by clicking through the Chase UR portal (8x)In total, that’s 300 United miles ($4.20 valuation) plus 950 Chase UR points ($19 valuation) for the $100 purchase — or 23.2% return in value.If you’re interested in seeing how many miles and points you can earn through the airline or hotel portal of your choice, use a shopping portal aggregator such as Cashback Monitor to see which other portals have competitive offers.