Where do you get these.  Received books from 2 different people sent in them and they look like they'd be much easier to ship with.  Googled it but the bags I'm finding don't look like the ones I received.  They are white on both sides, not clear, and thick plastic.

Thanks.

I've bought them at both Amazon and ebay.  I use the 6x9 size.  If you don't mind buying a large amount at a time, you can get them supercheap at the website uline.com.  I don't want thousands at once, so I only buy 100 at a time--less than $10, shipping and all.

I agree. I buy mine on eBay. You can search poly mailer and find several reasonably priced sellers. Office Max used to sell them too, but I don't know if they still do--there's no longer one in my area.

I see 2 kinds:   ones that look like manila envelopes and others that are more like a bag.  I'd like to try them but don't want to buy 200.  Are they available at a place like Walmart in smaller amounts?   Which kind are better?

I saw some at Walmart awhile back, so I think they still sell them

I'm using poly bubble mailers now.  Got them on ebay.  They have lots of 50 or 100 really cheap.

I purchased (100) 7.5 x 10.5 white poly mailers from Amazon for $7.00, plus $6 shipping.  This size is good for both paperbacks and most standard hardbacks.

I just bought some white poly bags, they were 4.95/free shipping for 25 of them. I figure I'll try them out first see if I like them, before I buy a bunch!

This is where I bought mine http://stores.shop.ebay.com/VALUEMAILERS__W0QQ_armrsZ1  They are reasonable and ship very quickly. I bought a couple of different sizes (I think it was a combo pack or something). I knew I would use them, so I wasn't afraid to buy a lot of them.

Thanks for the tip, Dory, I bought some from that seller.