Ever wonder about which type of bed is better to get your furbaby? The best word of advice is "observe."
If you often notice your pooch completely sprawled out in a sort of head-to-toe stretch, then a large, firm, rectangular or square cushion-type bed would work well. Be sure it's long enough so that your baby's legs don't hang off. If your doggie likes to curl up into a ball to sleep, then a soft, deep, cushy round bed would allow your little one to sink into cozy comfort as they compactly snooze.
Perhaps you've found your sweetie catching some Z's under a blanket, or maybe she's taken refuge in your freshly done pile of laundry? Then a bed with a thick, cushioney outer rim, like a donut-style bed, would be ideal. This way, your best friend can burrow into the edge between the center cushion and the rim, and feel safe and secure. Or try a trundle style sleeping bag for them to "tunnel" into.
Be sure that the bed you purchase is made of machine-washable fabric, and that it does not have decorative trim that can be chewed off or cause your dog to be uncomfortable. Make certain that the bed isn't too high which could make your dog reluctant to use it and stress their joints when jumping down. And always remember to tuck your baby in before bedtime for the sweetest dreams for both you and your little love.