We created this service for ourselves, used it for years, and thought it would be great to offer it to other people. We considered a free/advertising model. However, in order to keep the databases at peak performance it's best to know who is actually using our service. In other words, free customers would hurt performance directly, but also abandon their accounts and leave records lingering in the databases. Therefore we thought it best to offer a simple subscription model that allows us to immediately clean up the databases when customers cancel.
Currently the price is $19.95/month for unlimited broker accounts (i.e. unlimited usage). We considered tier pricing (and had it setup), but decided to keep things more simple. We're open to suggestions, so use the contact form if you would like to offer a suggestion.