Try either bulkammo.com or ammoman.com. or cascadeammo or cheaperthandirt.com or natchezss.com. One of these I saw had 1000 rounds for $179 recently.
Reminds me, I need to pick up some .45 my own self. Also, wholesalehunter.com has Blazer pretty cheap. When I find some I like I'll post back.
Best, -Coop