For an upcoming phone project, we've been quoted the following as options (yes, SIP is on the table too).

We're after 8 lines, with 3 "pinned" as outgoing and the rest available for In/Out as needed and have been quoted as follows:

ISDN 2

In blocks of 2, 285 each for install of each block, plus monthly rental of 15 (x8) = 1,140 install, 1,440/yr in rental.

ISDN 30

Minimum of 9 lines.
550 flat fee + 30/line for install. 15/month line rental (x9) = 820 install, 1620/yr rental

Analogue

99/line for install, monthly rental of 15(x8) = 792 install, 1,440/yr rental.

Since I haven't bought an ISDN line since.........2001, does these look to be about right, over the top, low?