There are many company that will come and pack your belonging for a good price. Most of you personal clothing can be shipped by Greyhound for a good price. They are cheaper than most other shipping carriers. Below is a link to moving calculator finding the cheapest carrier for you. http://www.movingcompanies.com/
When you move anywhere you have to calculate the cost of the move vs. the value of the items you are moving.
Since you are looking for an inexpensive way to ship things, obviously money is an issue.
Seriously look at what you are taking, and see if selling it where you live now, and rebuying new items would not be cheaper.
There are no CHEAP methods of shipping. UPS, Fedex Ground, or renting a U-haul and taking things yourself.
I noticed from your comment above, that you wanted to ship a mattress - not smart Unless you have a $ 5000.00 fancy shmancy mattress it will cost you more to pack and ship it without you putting it in your own U=Haul truck, than buying a new one at your destination.