Yeah I was on craigslist and someone was selling like 115 volumes of manga for like 3 or 4 bucks a volume so I offered them $50 for 25 volumes I wanted and they offered the whole lot for $100 and I had to take them up on it. >.< I ended up with like ten duplicates of stuff i already had though.
Cheapest I've found so far is $15. I'm trying to find out what it would cost through media mail since that's usually cheapest but I haven't been able to figure it out yet through the USPS website. Ill update you if I find better information.