A girlfriend of mine that has been on this website for quite sometime that she has over 800 Positive feedback and she has tired the flat rate envelops before and they dont fit very well. She has found that the medium flate rate box works much better that is why.
I just had three pairs of jeans sent to me for 10.20! So it's possible to ship for a lot cheaper as long as you supply box yourself and do not ship flat rate.