smartFox Server Alternatives?

Is there any less expensive alternatives to smartFox yet for building online mmo’s and mmorpg’s with Flash? I have not developed a multiplayer game in years and smartFox2 being 4.5k/server USD instead of 2.5k per server now is starting to get a bit steep…

Also, is it possible to do a server>client push over a flash netconnection somehow? Eg, using amfphp, give the connection an Id number saved serverside and push back to the client realtime without using polling.