> how often do you have a session per week?

once every week (fridays)
and twice every second week (fridays and every second tuesday)

> how often do you have a session per month?

um... depends how many weeks in a month i guess.. on the assumption that there is four weeks i get... six, i guess.

> and, if you have have bi-weekly sessions or more, how do you afford such frequent sessions?

sliding scale. i was very lucky indeed to find a t who i wanted to work with, who wanted to work with me, who offered me an affordable rate.