As so many others have said: yes, good people are expensive. And if you expect to grow to a non-trivial size, hosting/servers/bandwidth are going to cost you.
There is also the issue of leverage. If you need $500k, you don't raise $500k, because when you run out and start looking for more money, your negotiating position is very poor. Instead you raise $2M, then start to talk to investors again when you have spent half of it.
In my experience marketing is not a significant portion of expenses for a startup.
I email myself the moment I think of something, then process my email inbox once a day. When processing, I either do the thing (if it will take less than two minutes), or file it with a project or under someday/maybe. For filing, I just have a bunch of folders and files on my hard drive. Nothing fancy.