Here's the low down on money, phones, and Internet here at FOB Bernstein (Caldwell is not much different except you can go to finance any time you want).

Money.  Cash is king.  The PX will take credit cards but nobody else will (e.g. haji shops, etc. -- there's not much in the PX and it only gets restocked every few weeks).  There's really not THAT much to spend your money on here, anyway, once you get settled and have the essentials.  However, when you need money, you get it from finance, who visits the FOB 2x per month.  The finance policy everywhere seems to be that you can get up to $350 per month in casual pay (direct deduction from your LES), and you can cash up to $200 in checks per week.  I believe that since finance is only here every 2 weeks, roughly, that you could probably cash up to $400 per visit to finance here if you really wanted to.  I would show up with no less than $200-300 in cash, and go from there once you figure out how much you'll be spending.  Laundry is free, food is free, haircuts are free but tips are expected (a few $).  Snacks and magazines and trinkets from the local shops are about all there is to spend money on.  Movies are also popular -- you can get local DVDs with 1 to 4 movies per disc for $5-$8.  Even new releases.  Most of these are not great quality pirated versions, and often they won't play completely or have other issues, so you get what you pay for.

Phones.  There are 6 phones on FOB Bernstein.  I think they were installing 2 more this week.  There's a 20 minute time limit for usage.  Most of the time the line for phones is less than 10 minutes.  They use Segovia, and you get a virtual calling card (just a number) through segovia's website.  It's quite cheap, about $.04 or $.05 per minute.  You can also use Dialpad or a similar service and take a microphone headset to the MWR's computers and make calls from there.  I've not done this but many people do.

Internet.  MWR has 20 computers in one location with webcams and about 10 or so in another location (with the phones) which I believe also have webcams.  There's a 30 minute limit on internet usage.  Both phones and Internet require that you be in full DCU uniform to use them, which can be a PITA.  You cannot hook up a personal computer to the MWR network (unless you're doing 'updates', in which case you can get away with it from time to time).  I strongly recommend that you bring a thumb drive (or buy one from a local shop, they're pretty cheap here) to use to transport files, pictures, etc.  Also if you have a digital camera, it's good to bring a laptop if for no other reason than to be able to download your pics from your camera.  You can also get Internet set up for your quarters, if your chain of command approves and supports you.  There are several options here, including getting a hook up from MWR's system if you're near one of their facilities, or going through one of the locals and getting a dish set up.  I went the latter route for my platoon's living area.  We're paying for it out of our own pockets but many units will have unit funds available that could cover it.  Our cost averages out to about $30 per person per month.  It's more than worth it to be able to use the Internet on our own computers from the comfort of our quarters, rather than having to walk a mile in DCUs and kevlar to be able to use it for 30 minutes at a time.

If you have more questions, let me know and I'll try to tell you what I can.