campacopia.com has very very cheap shipping, check it out, was a few dollars. The more online vendors who realize that sending something light via first class mail for 3 dollars or less, the better. A few are starting to do that, makes sense for light gear after all.
Re using sawyer stock bags, just touch them, then touch an evernew, roll them both up a few times, that's why I bought the evernew 2l, which I like better than my platys anyway, I'm not buying more platypus bags. For sawyer stuff, a bag that starts leaking and fails miles from nowhere is useless, doesn't matter how cheap they are per 3 pack. And if you bring two in case one fails, that's more weight than one decent quality one like evernew. I wish they'd use a few mil thicker bag, but they don't, maybe some forum threads like this will wake them up.
Anthony A, near as I can tell from this thread, unless you have old platys, this thread is largely agreed that the new platys aren't sealing well, and even if they do seal, the threads are too small and might fail at any time even if you do get them to not leak. The cross threading isn't subtle, it happened to me the first times I tried it, and I'm reasonably mechanically tuned in.