It's pretty easy to be able to get AWS credits for about ten cents on the dollar in the digital goods section of this forum. I'm currently running the tipbot aeonbux on a micro instance, and I've just used a bunch of swap and commented out the auto saving in the daemon, been running fine for several months. I think that would suffice for a remote node, in which case i think the monthly cost is $10-15, but you only actually pay 10% of that.