Other than Sasuga, Animaxis, and Kikiwai...
there are three other places I recommend...
Kinokuniya East Coast
Kinokuniya West Coast
The shipping for Kinokuniya is about $5-10 per order each issue is about $5.50 and for Mangaoh its like $10-15 for shipping and 390 yen per issue ($3.66 USD)
All three of these sites have the manga instock at the moment.
Here's the catch-22...all of these sites are in Japanese meaning in order to find the titles you have to search with the Japanese Kanji (which is 鋼の錬金術師 ) and need to understand some Japanese (Mangaoh which is located in Japan actually has an english based sign up for foreign customers...you need to create this account in order to be able to order)
It really depends on your flavor...Kinokuniya ships UPS Ground and if ordered from the opposite coast...ie I live in Miami, FL and I had to order from the west coast store...it takes about a week...
Mangaoh comes straight from Japan...its a little cheaper per issue and comes in like 2 days because its sent EMS
The order forms for Kinokuniya are pretty easy to understand but if you need help I'm sure there are enough people on the community that can help translate it...myself included
So have fun and happy buying
PS-please don't go and buy a bunch of the issues to horde and possibly resell...I'm giving this info because there is a genuine interest in exploring the manga...not exploiting it.