They have two options depending on what you are looking for; a tenant involvement and a no tenant involvement package.

There is another popular one called VRCalendarSync.com I believe that you can purchase the premium package and it will do everything for you.  

(if you buy the middle package... you get 3 sites... and you need the middle package regardless, so you get your buyers site for free)

Number of packages/letters processed?

The BiggerPockets package has inspection forms, pet forms, application, etc. 

These companies range from 4K-12k for their packages.

You also agree to pay an additional $200.00 lease violation fee each time we determine, at our sole discretion, that smoking has occurred in your rental unit, due as Additional Rent.

It would be cool if the plus package included a 1 month free pro membership or something.

When a property has a loan that is way over the value of the property (like if at the time real estate was higher, but has now depreciated, a bank can agree to take less at auction - it's completely at their discretion).

In practical terms, an example of what that means is that 3-4 months before your BRRRR appraisal (when you're still doing rehab work), start visiting the open houses of all of your future comps, get the seller's disclosure packages from listing agents (pretend to be an unrepresented buyer if that's what it takes), and find out in writing from the seller of that house why that comp is about to sell for $50k or $75k less than what you think your property will be worth.