I looked at the nanoBTS also, but the ones that can operate in 900MHz and hence not be illegal in the US are still pretty expensive. Though you do have a good point that factoring in the cost of a -48v power supply, the 6601, DUG20, and RRUS, it'd probably be pushing $1k anyway.

Hi Ben, I'd be interested to know more precise details about what
Ericsson gear you are looking at.

This is for 2G GPRS experiments, correct?

I'd also wonder what it is you are interested in doing with GPRS, I've
generally found that it's pretty much unusable for most applications
running on a modern IP stack. You can do ICMP "ping", yes.. but not so
much more. Maybe with (only) one phone on a TRX fully configured for max
packet data channels, you should be able to establish a connection to a
web server, XMPP server or even an ssh session.

If you configure EGPRS a.k.a EDGE, then there are more possibilities,
but I think the EDGE support in osmocom for the RBS is still considered
very much cutting-er..edge..

I have some Ericsson RBS gear and I have not as yet, got it up and
running with either GRPS or EDGE. (Not saying it should be difficult, it
just got pushed down my priority list) We do know that it's possible,
although sustained operation with multiple MS, I believe, has yet to be
tested. The Ericsson RBS gear also presents a not-insignificant need to
look at power supply, (and consumption) RF attenuation, and last but not
least, Cooling!!

The SysmoBTS 1002, on the other hand, is pretty much plug-and-play at
this point.

Maybe somebody else can expand on GPRS support on them, as I don't have
one, but an Ip.access nanoBTS might be found within the budget you
mentioned.