They retail for about $20 and you can them find on Amazon and in just about every baby store out there.
The Bitta Kidda sleeper goes for about $25 and the sleep sack for about $34 on Amazon or BK's website.
The swaddle retails for about $30 and the sack for $35 on Amazon of NB's website.
This one goes for about $40 on Amazon.
Lullaby Breeze Breathable / Washable / Waterproof Crib Mattress Cover - when baby starts rolling to tummy, it's terrifying!! But this mattress cover is breathable, giving you peace of mind to let baby go ahead and stay on their tummy if that's what they like. Check out my review here.
QuickZip Sheets - just zip the top part on and off to wash, no need to take the whole mattress out of the crib! They make sheets for all sizes up to California King, and also make pillow cases and waterproof crib mattress covers. Check out my review here.