SNMP monitoring app for traffic graphing?

[JamminR]

I want a reasonably easy and free solution/monitoring/tracking application for an SNMP switch.
I've spent hours this morning and last night on Google, researching.
Seems every time I thought I'd found something free, it required a VM, or 2-3 other package prerequisites, or had to know the SNMP oIDs, the difficulty/challenges go on and on.
My dream app would be to, run the app, type in an IP address, SNMP strings, scan the device, select what I want to monitor, then it just work from there tracking trafffic use on each port.
I'm running Win7x64. It doesn't even have to be a service (I'd almost prefer it not be...just run the app and let it go for hours)

Background.
I'm about to hit my 300GB transfer limit for the month of January. It will likely happen this evening.
(I get 3 'courtesy' overage passes, but, it's only the first of the year, and I've never had to use them before)

I have about 11 internet connected devices within my household at a maximum point.
This 'average' number wanes/falls throughout the day as mobile devices I own connect (or not if not nearby), and the 2-3 PCs I use are awoken/put to sleep.
At the top of my network pyramid, I have Cable modem < Router < 8 port SNMP capable switch
I want to monitor all the ports on that switch to localize just what the heck is going on through out a time period.
I went radical and shut down several apps/services last week, and still end up using ~4-5GB a day (according to my router, my ISP's meter varies a bit)

Though I'm 99% sure I'm going to kill this month, I'd like to know for future just what's killing me.
It's not open wi-fi. (First, I don't have an open one, and, there are no DHCP addresses leased on my router that aren't already accounted for).

[Stickly Man!]

Hmm, have you checked this article?
http://www.howtogeek.com/141135/it-geek-monitor-network-devices-with-snmp-simple-network-management-protocol/

I briefly skimmed through it, and it looks like these tools can do what you need them to. At least, simple bandwidth monitoring. As a side note, this looks interesting and I'm now interested in setting this up on my own router (which probably doesn't allow access to SNMP. Dang.)

[JamminR]

Yep, found that link while Google'ing.
Some of the apps it gives instructions for are pretty large/extravagant systems.

I wanted a reasonably small app that didn't install huge systems of IIS/perl/etc, just a app I could run, give an IP and SNMP community string, and go for a few hours/days.

Though I still have that as a side quest, all my research time since this afternoon is now spent to find out which custom firmware I want to use, and which will be compatible with my older model and already cusomized by SamKnows project router.
I figured out that SamKnows is using ~4GB a day to monitor various network things beyond my local LAN. (~110-120GB of 300 a month)
Though when I needed it 4 years ago to prove to (me, Comcast, FCC) that Comcast was crap in my area, I've not needed it in 2-3 years. They finally updated, and meet/exceed advertised speeds during prime time.
There's no way to permanently disable the SamKnows tracking functions, other than new firmware or new router.
I'm going the cheap route (custom firmware). Time is expensive finding out which versions/what mods it can run, then which I want it to run from those it can.
It may still end up being moot point when I brick it anyway = new router.

[JamminR]

Ok, so, after bricking my router, waiting 3-4 days for a TTL serial to USB cable, and then debricking, upgrading, changing, updating to different, I think I now have a firmware with features I like.
It's a Toastman USB 1.28 build.
Too many open firmwares to choose from, still missing one feature another had, but leaves 2mb for JFFS system to store other stuff and still connect to my Win server (cifs) for logging/other transfer
stuff.

My firmware is now saving me ~100GB a month.
I'm only at 82G now of my monthly allotment of 300. And that's with my spouse sick at home last week watching marathon seasons of various shows on Netflix.
Not only can I see which devices are using the bandwidth from GUI, I can tell when/for how long.

Now on to my next help wanted question;
It's been almost 15 years since I got to play in a *nix environment that I owned.
(Played in career up until about 7 years ago)
Doing a netstat while ssh into the router itself gives much stuff, most of which I know/have experience with, except for the following UDP ports.

udp        0      0 localhost:38032         0.0.0.0:*
udp        0      0 localhost:38000         0.0.0.0:*
raw        0      0 0.0.0.0:255             0.0.0.0:*               255

Though I've always been happy with my Google-Fu - I can't find any description of what those ports are/what they do. ONLY many other mentions of them.
I'm guessing 255 is a broadcast listening agent of some sort.
But, can't for the life of me find 38000 and 38032 explained.

Can anyone here shed light as to what they are?
(And, if you have a WNR3500L laying around, will give a tutorial/tips/steps for how I updated my router to TomatoUSB 1.28, Toastman or Shibby)