Well the club which is connected to the Masters Series tournament is a really nice place. I played there back in 2000 when I was on a holiday there, which was no problem. I can´t remember the price, sorry.
It´s situated just next to the Olympic stadium, which is a bit far out, but not too hard to get there - it´s also called Foro Italico out there
The address is: Foro Italico, Viale Dei Gladiatori, 31, Roma
Here is how to get there : http://www.inter****onalibnlditalia....oDoveSiamo.asp
Else try finding Rome on Google Earth and then type in tennis in the search field - then it´s also possible to get an idea of where the clubs are situated
Hope it´s useful