I'm with Rodney . . .
USPS is the best way to go for T-shirts---
1 tee normally ships in the US for $3.85 . . (under 1 lb)
4-5 Tee's is just at or a tad over 4 lbs -- however you can get 6 - 8 Tee's in a flat rate priority box for $7.70 ..
of course you have to learn how to fold the tee's for them to fit nicely . .
.. I have been told that I take to much time in my packing department . . L*~
anyway,...T-shirts orders over 8 -- it becomes a science -- as far as who to take your shipments to for the best rate on weight . . .
you can get your USPS shipping supplies from your local post office or order them online since the supplies are FREE . . (I loooove FREE) . . go for it . .
Personally, I use a flat rate e'lope and a tyvek e'lope for shipping 1 or 2 Tee's
3 or more Tee's then I tyvek the tee's and then put them in a priority box...
buyers like the idea of weather protection and the extra steps almost insures a repeat buy . . of course when the buyer opens their package . . it's like Christmas again . . LOL*~ . .
for orders that I ship to a different address other than the buyers address, I included a Greetng card from the gift giver to the gift receiver at no extra charge to the buyer . . . WHAT a great response I rec'd from that little FREE add on . .
and of course . . ALWAYS, always include a few extra business cards with a discount on the back for the gift giver and the giver receiver . .
your cost on giving FREE greeting cards and sending extra business cards, is less than 25 cents a buyer . . . BUT 25 cent 'might' bring you additional business in the near future . .
Diane