I would like to suggest using the two-gallon-sized Ziploc freezer bags (the
freezer bags use a thicker plastic than regular ones)? These work *great*
for freshly-baked bread, and they're easy to find. For smaller loaves you
can also use the gallon-sized bags. Depending on the size of your loaves
you can sometimes put two bread loaves into a single two-gallon
bag. Unless you intend to give the loaves in their bags as gifts to
someone there's no requirement that the bags be shaped exactly like the
loaves themselves.
Make sure that your bread is thoroughly cooled before bagging and freezing
it -- otherwise you end up with condensation that turns into ice in the
freezer and tends to ruin the lovely homemade bread. To make it as
airtight as I possibly can, I generally "zip" the seal all the way except
for the last inch or two -- then press out as much air as you can and
finish sealing the bag. This works well if you sort of roll the bagged
loaf on the counter gently until the bag is basically wrapped around the
loaf up to the point of the top seal, then squeeze out as much remaining
air that you can and finish sealing.
I've used the Ziploc bags for years with great results, and you can often
get a nice discount or coupons on them at the grocery to make them very
inexpensive. They're easily re-used -- just rinse out with warm, soapy
water and dry (I drape them upside-down over my wooden spoons which are
stacked upright in an earthen pitcher on my kitchen island -- they dry more
thoroughly if you open up the bag and use the spoon as a "hook" while it's
drying).
NOTE: I do NOT like the bags with the plastic slide top used for sealing
(I believe they're called "Easy Zipper") -- these do not create an airtight
seal at the corner where they end their "slide" and end up ruining my
bread. I prefer the bags with no "zipper slide" since they make a more
reliable seal, called the FreezeGuard seal. Also, I believe Ziploc is now
making a new bag called Ziploc Double Guard, which is a bag-in-bag design;
however, they only come in one-quart and one-gallon sizes.
Hope this helps,
Joan