Hello I have been in the shipping industry for over 15 years and woud be happy to help you with anything - first off I would always reccommend UPS or Fed-EX and that is because they are both very reliable also each carrier will provide a tracking method and declared value (ins.) up to $100.00 with each package and not charging extra for these services - the post office will charge an additional fee on both of those extra services . As far as the cheapest method it depends on the size of your package not just weight also where it is being shipped to, so for example it weighs 40 lbs if your box stays under 20 X 20 X 20 then your ok. The rates are based on the dimisions of each box another example say your package weighs 10 #s but it is in a 20 X 20 X 20 box then you will pay shipping based on a 42 # rate. So the answer to your question depends on other facts. I would be happy to help you determine the price if you can provide me with the size - and destination also would you be shippng this ground? Express packages are much higher.
Other people asked questions on various topics, and are still waiting for answer. Would be great if you can take a sec and answer them