UPDATE:i forgot to update this!
we did end up waxing the tops, just bought sealing wax that was on clearance at michaels and followed the directions. pretty easy, altho as some others have mentioned, use an old pot! the wax is hard to get out, so we just let it harden and tossed the pot.
we added a scent to the wax, and everyone has told us how nice they smell (plumeria)!
we took them to the post office, and got lucky. it was busy so the clerk weighed 1 bottle and it came to $1.31. instead of printing and weighing each individual bottle (which would have taken a LONG time) she sold us a few sheets of $.90 stamps and an equal number of $.40 stamps, and told us not to worry about the extra $.01 she just charged us a misc charge for $65.00 (to send 50 bottles). then we took the bottles over to an empty counter and smacked the stamps on ourselves. it turned out pretty cool, we got these tropical palm tree/beach stamps that are out right now, and the $.30 stamps were the little ones that spell "celebrate", so it looked really cool on the bottle, way cooler than a regular printed barcode kind of stamp. make sure to ask if you can do it this way!
we mailed them at closing time on a monday night, and by the next afternoon people were calling to tell us they got them! altho, the one we sent to chicago still has not arrived everyone else has gotten them.
we just saw on at dougs parents the other day, and it looked really neat with the torn wax and stuff, they had it sitting on the mantel above the fireplace. the postage was hand cancelled, and it looked so cool.
my biggest bit of advice on these is watch how much sand you put in if you want to cut the cost of postage. we only had about 1/4 inch sand in each bottle, plus about 7-9 tiny shells, 2 umbrellas, 9-10 little palm tree confetti pieces, the postcard and twine.
hope this helps! any ?? just ask!