How to save on holiday shipping

This post comes from Kelli B. Grant at partner site MarketWatch.

It may not just be big sales prompting shoppers to buy more online this year. It's also the recent proliferation of free-shipping offers, experts say.

Oddly, the key sign that free-shipping promotions are better is that the size of each online order is shrinking even as total online sales rise. "Shoppers don't need to buy as much to get free shipping," says Jay Henderson, strategy director for IBM Smarter Commerce.

Online sales on Black Friday, for example, were up 21% overall, but the average individual order fell 4.7% to $181.22. Consumers also checked out with 12% fewer items in their carts, an average of 5.6, down from 6.4.

Free shipping has also become a competitive point for retailers looking to get more shoppers to buy. Sites have amped up the number of no-strings free-shipping offers to better compete, says Luke Knowles, founder of sale-tracking site FreeShipping.org.

The growing deals bode well for online shoppers looking to save, but there are still some considerations to weigh before checkout:

Compare available offers

More free-shipping offers kick in automatically at checkout, instead of requiring a coupon code, Knowles says. That's ideal, especially with sales in play. But some sites and promotions still depend on free shipping codes and limit shoppers to one discount code per order, forcing people to choose between using a code that gives them a discount off their order and one that gets them free shipping.

If that's the case, test both options to see which is more valuable, Knowles advises. Options like in-store pickup or site-to-store shipping, which are typically free, can also free up that coupon code for use as a discount.

Ship to gift recipients

If you're traveling for the holidays, it may be cheaper to use free-shipping offers to send gifts directly to, say, Mom and Dad's house instead of paying bag fees to haul them there in checked luggage, says George Hobica, founder of Airfarewatchdog.com.​

With the exception of JetBlue and Southwest, U.S. airlines charge a fee for even one checked bag. That could set you back $14.99 to $45, depending on the airline and how far in advance you pay the fee, according to SmarterTravel.com. If the bag weighs more than 51 pounds, fees can add another $50 to $200.

Letting the store handle shipping is likely safer, too. Airlines' reimbursement for lost, stolen or damaged items in checked bags typically excludes electronics, jewelry and other gift-type items, Hobica says.

Reduce fees

On orders where there is a shipping fee, look for options to cut the cost. Retailers including Wal-Mart and eBay have added same-day delivery options in recent months. Amazon.com is also testing a $7.99 monthly fee for its Prime service, which regularly costs $79 per year for free two-day shipping on all orders. In either case, the fees may work out to be cheaper than charges for fast shipping methods.

Check the delivery window

Picking a particular shipping speed doesn't mean you'll get that order in five to seven business days, or even overnight. A better gauge is the site's expected delivery window at checkout; most allow themselves a few days to process orders, says Jordy Leiser, the co-founder of customer service rating site StellaService. There may be later windows for popular items on order.

Some sites also institute cutoff times to have an order processed that day.

On the plus side, reports this year indicate most sites are getting packages to customers at the earlier end of their delivery windows. "The worst thing for retailers to do this time of year is to set a bar and then miss it," Leiser says.

More on MarketWatch and MSN Money:

• The elephant in Amazon's mail room
• What Starbucks' $7 coffee is really worth
• 3 tips for better holiday tipping
• MSN Local: This week's local circulars
• 25 ways to save on holiday shopping
• 10 tips to get the best price online