Are there any conversion tracking tools out there that you guys can recommend?

Google analytics will do this for you. If you've got GA already set up, visit "Admin" (Cog on bottom left). Under the right hand side 'View' column is Goals.

Click through to add your register page as a goal. It's a custom goal, of type 'destination'.

Now, every time someone converts, it'll attribute this back to the source (betalist in this case) and report how well they convert compared to other sources.

Mixpanel funnels can be good once you put the time into setting them up properly. GA conversion goals are good enough initially. Highly recommend checking out their reverse goal path.

i'm a really big fan of funnel reports, where you define some sequence of events (landing -> signup -> paid, etc..) and can see drop-off %'s at each point. I've found Kissmetrics to be the best. there you can segment the entire funnel on just about anything. handy for seeing metrics between releases, by device, varied entry points, etc.

Chartmogul for you $