Ask HN: Project Collaboration Web Apps?

So, someone submitted proofhub.com earlier today and the software there is almost perfect. However, it's beta/alpha and is lacking some serious features. I cant invite a new person into an already created project I cant make someone else an admin so they can create projects Just a few little things like that... I'm wondering if anyone else knows of some "ready for prime time" software to do this via the web... and without breaking the bank. I'm thinking $99/month OR LESS for an "unlimited" type account. What's everyone else using?