Dirt poor? Underleveled? Fear no more, since your dear bandage is going to tremble your world with the following advice!
I personally have learned to live by the following (personally) game-changing rule as the hard support (which is easily my favorite role out of 'em all):
You always get 100 gold per minute from the periodic gold income thing.
What does that mean for me as a barebones support player with a tiny soul and no given love? Basically, you get your money for a set of wards by waiting... or rather, spending 1:30 minutes of game time to get the money for buying the set. For sentries you must spend two minutes because they cost 200 gold. For dust you'll have to spend a bit less than two minutes to get them, and so on.
The point is, as the hardest support...
Time is your currency!
Over time I learned to predict where to place my item choices on the overall game time according to what was going on in the game. As a hard support you tend to be (and preferably should be) the "ward bitch" during the entire game, so you must act accordingly.
Basically, you could always get the both sets of wards with 350 gold, which translates into 3 minutes and 30 seconds of gametime - which is less than how long it will take for observers to restock! So if you are going to take care of the both ends of warding, which you should at least with observers, you will basically get (sigh) 250 or 450 gold in between buying wards (over the course of 6 minutes). That is, if periodic gold stays as your only income.
You can always clear pull camps and/or go gank other lanes to increase your income, or just trying to kill the opposing laners with friendly ganks and the like. Find opportunities and take 'em. Mid ganks are always appreciated, believe me.
When talking about gold, remember that your team is always ahead of you as the priority 1, and you should secure and help them farm before you start getting your own stuff. Use your money to help the team, and then think about what you should be getting for yourself.
To sustain such a weak (but awesome) player role, playing heroes that are fine even without any items at all, like Lion, CM, Kotl and the like is pretty important. I don't really need to spend any gold on myself to keep the team up and supported (and the map warded - so useful, so important) when you have a hero that can get mana from a passive, or a mana leeching ability, or just by having generally good gameplay potential even with some very basic low level skill setup (something like shadow shaman, dazzle and io comes to mind).
It is a pretty good thing to know your hero really well down into the details too (like stats, base damage, armor, natural regens, mana pool efficency for skills, etc.) to know how to maximize your potential with the little what you have. This can mean something like timing your upcoming planned ganks when your mana has been recently used up, and you're waiting for it to regenerate. Do some quick simple math in your head to judge at what point in the game time your skills can be used again, so you can start moving forward asap. Playing the fifth role is all about efficency with the little whatever you might have, because you don't really have anything else in the first 10 minutes of the game or so.
As for items, brown boots are pretty awesome to keep you mobile around the map doing more things in less time (and time is constantly ticking in the laning phase for you - use it as efficently as you can, while you can!). They also help you get away from dangerous chasers easier, and you to catch up fleeing opponents. Also makes lane harrasment a bit safer so you can retreat quicker from there. Frequently I tend to pick up brown boots as my first personal item just because of their overall practicality. If I'm fine with my movement speed, I
About being underleveled...
Being underleveled is actually just fine if you know what you're doing. Just don't mind even if you're like 4-6 levels behind your teammates if you have helped them get bigger. I tend to always be pretty "underleveled" every game because I tend to move away from the lane to roam around ganking/warding/dewarding/stacking camps in the map. You just need to 'unglue' yourself from just sitting on a lane because your carry probably needs it. If you're a safelane support, ask yourself if your carry is actually fine by being alone farming the creeps on the lane. The safer your carry is farming creeps by him/herself, the more you can actually go outside doing random support shit (provided you still have emergency TP (costs only 100 gold or one minute of game time) for saving your carry from the worst thing ever - the halt of gold income).
Your levels may not even realistically matter that much! It is about how much impact you can do with what you have in your disposal at the moment. If you play some heroes with really useful ultimate like Shadow Shaman though, then you probably want to amass more xp to gain your awesome skill for greater good.
When the game progresses onwards to the midgame, you will find that even though it feels like you can do almost nothing with your petty arsenal of items and skills, you still manage to get up from the craphole and gain more levels and gold by helping your team doing what they're doing. Assists happen, towers will fall, you take part in pushes and ganks... It will start adding up. You will have more spare money for items you would like to have for yourself. A bracer? Anyone?