I have written a script based on API v1 while it working... It could publish/queue like 50 posts at once in a couple of minutes. But now with API v2 you need to register application (
http://www.tumblr.com/oauth/register) in order to get the key that you can use to actually post things (and make a bot).
I could program all that but the question is - once they find out that you're using that application for mass posting/spamming they can delete all posts and/or all blogs that used the application so it makes me wonder - is it really worth it...
So buying anything based on V1 will not work and you're just wasting your money.
Only thing that could work is some browser javascript mod that would emulate you filing in and posting forms, but haven't found anything that works..