Thanks for asking about this.
On the 'My Plan Info' page, we show an info message to users subscribing to the 'Basic Plan' (e.g. $2.95/mo plan) page that gives this information:
"Out of 15 free posted listings allotted to you this month, xx remain.".
On the 'My Account Activity' page we show charges and credits since your last invoice. You can use this to monitor insurance charges that for policies you buy during the month, but during the month, it doesn't show the 50 cent each charges for auctions over and above the 15/month limit, nor does it show (again during the month..)any charges that may be due to This is because we only compute the $$ value of these as part of our billing cycle.
I think the idea you are bring up in your post...of being able to track what you spent during the month so you can see what your charges are before invoicing...would be a good idea for us to implement on the Auctiva site, and I will look into it for a future release.