Once you've confirmed that the online retailer runs a legitimate operation, now it's time for fun...shopping. I often find that with furniture you get what you pay for, so if the price is cheap, the quality probably is too. This is fine, I have a mixture of expensive and cheaper furniture and they seamlessly coexist. I often find that one expensive focal piece in the room is all you need, but if you can afford more, by all means.
Good review sites will often have all of the details you need on a retailer like the shipping and return policies. These can make or break the deal with many people. The good news is, a lot of online retailers are realizing this and offering free shipping deals and better return policies.
I often pass on retailers that charge a lot for shipping fees. Even local home decor retailers can charge several hundred dollars for delivery on large items. Most online retailers offer reasonable shipping prices to your door, but it's a good idea to add the items you want to your cart, and verify the total with shipping to see if you still want the items.
Return policies will vary quite a bit. Some retailers offer no-hassle returns where they e-mail you a shipping label and you put it on the box and then drop it off at a UPS or FedEx location. Some retailers charge restocking fees for large items returned, so be aware of the policies before you buy.
If the company is online and only has a store in one state, you may not be charged sales tax on your purchases. This can save you hundreds of dollars upfront, if you're making large purchases. Many online companies will also price match their competitors. So shop around and find the best deal. Once you find it, if they don't offer free shipping, find a competitor that does and you will likely be able to save even more money.