As far as the actually mailing portion of it goes, I would suggest taking it to your local post office if you don't know the weights/postage for your shipment. Shipping with USPS is cheaper by far than UPS or Fed/EX, unless you're doing things like tracking, insurance, etc. which UPS and Fed/EX both automatically include in the price of their shipping (up to a point). You can also just put a number of stamps on the envelope to cover the total postage, but beware if you don't know your weights; if a package is shipped with incorrect postage it'll just end up back at your door in a couple days and you'll have to get a new envelope and send it back out all over again.