You're already gotten some reasonable advice on this; but there are a few important points which have yet to be addressed...
That budget is near-certainly inadequate. At that price point, you'll be limited to "contractor special" open-frame portable generators rated for MAYBE 5kW, tops. In addition to the rather skimpy output capability, such generators are, as a class, generally undesirable for this application, for several reasons.
Much of this has already been discussed here recently; so rather than repeat all the gory details again, I refer you to:
http://www.garagejournal.com/forum/showpost.php?p=3557426&postcount=13
http://www.garagejournal.com/forum/showpost.php?p=3602131&postcount=12
http://www.garagejournal.com/forum/showpost.php?p=3615476&postcount=5
http://www.garagejournal.com/forum/showpost.php?p=3617806&postcount=10
http://www.garagejournal.com/forum/showpost.php?p=3618068&postcount=12
http://www.garagejournal.com/forum/showpost.php?p=3619473&postcount=14
Plus, a decent 30A "shore power" cord to connect it can easily cost upwards of another $100, depending on the length you need:
http://www.defender.com/marinco-shore-power-cords.jsp
I can't really tell for sure, due in large part to the illegible hand-written (in pencil?) labels in those breaker panels. (SIDE NOTE:
WHY don't people take the ten minutes needed to make up PROPER typewritten or Dymo/P-Touch printed labels for this stuff; or better yet, just maintain a simple one-page word-processed "cheat sheet" posted on or next to each breaker box?!?)
That said, the ONLY loads which can be powered from the generator are those for which the branch breakers live in that small sub-panel. It would behoove you to carefully identify ALL of those loads NOW, and make up that "cheat sheet" I mentioned above, so that you will at least know what you've got to work with when the time comes. And NOW is the time to make any changes you feel are essential.
As for "Which breakers to turn off and on..." There's really only one thing to do: Note the two breakers at the top of the sub-panel. Between them, these determine from which source that sub-panel gets its power, either the feeder from the main panel (specifically, the dual-pole breaker in that main panel labelled "GEN PANEL"),
OR the incoming feed from the generator. The little brass-colored "brackets" covering the handles on these breakers appear to be a crude form of interlock, which is intended to keep you from being able to have both breakers live at the same time (which would be a potentially lethal prescription for disaster).
So, assuming you're using a portable generator such as you originally mentioned, the "Ooops, the power went out" tapdance would go something like this:
1. - Haul the generator out of storage and place it in a SAFE location, well away from the building itself and NOT in any even semi-enclosed space (such as a garage, carport, porch, etc.).
2. - Either fill the (should be bone dry for storage) fuel tank with fresh gasoline, or connect a propane cylinder to the genset and open the valve, depending on how your particular genset is set up.
3. - Get out your shore power cord, and use it to connect the generator to the dedicated power inlet plug located adjacent to the sub-panel. (As mentioned by "theoldwizard1", that is NOT an ideal location; but it's what you've got, for now.)
4. - Start the generator.
5. - Cuss a lot when the generator does NOT want to start. After all, it's been sitting in storage for maybe two or three years, more-or-less forgotten until you suddenly "need" it. (And Ghod help you if you left old gasoline in the carb when you last put it away.)
6. - Try again, maybe with a small shot of ether-based "starting fluid" down the carb throat.
7. - Lather, rinse, repeat until the generator finally starts.
8. - After the generator has been running long enough that you are confident it will KEEP running for awhile, go to your breaker panels and prepare to switch the "emergency" loads over to generator power.
9. -
IN THEORY, you should be able to effect that switch-over by simply throwing BOTH of those interlocked breakers at the same time. However, even assuming this works "correctly", it can potentially put a LOT of load on the generator, all at once, which can cause it to bog, stumble, stall, etc. (and besides, the unstable output waveform produced when this happens is NOT good for whatever loads you're running off the genny). So it would be better to FIRST throw ALL of the branch breakers in that sub-panel to their "Off" positions, then throw the transfer/main breakers to the "Generator Power" position, then individually throw each of the branch breakers back on, giving the generator at least a few seconds to adjust/recover between each one.
10. - With any amount of luck, your "emergency" loads are now running off the generator. You can now look forward to the "Shut Down / Re-Fuel / Re-Start" tapdance, every few hours for the duration of the outage.
It looks a little odd to me, too; but I
think it really is an interlock. I sure hope so, anyway.
I disagree, for the reasons mentioned above and in those prior posts I cited.
I presume that you're getting that figure based on the 30A main breaker(s)? Yes, the simple arithmetic of that would imply about 7.2kW maximum total load; but do we really know that is the limit of the PANEL, per se? If those breakers (and the feeder cable from the main panel, if need be) were upgraded, could the sheet metal box itself not support more load? I saw no markings to indicate a real "rating" in the pix posted.
