mrsmarquis:

If you don't want to risk losing a package at least write them regularly.

I found some patriotic cards at Dollar Tree - 2 for a $1.00 - big enough to write practically a whole letter on.  So if your writing letters/cards, they are a good source.  They have blank ones, birthday cards, etc.  I actually bought our local store out:)  With a couple of postcards inside, they still go for regular postage.