I recently bought a condo that has a window a/c unit. A very, very, very old window a/c unit. I am trying to conserve/save money, but I don't understand the idiosyncrasies of the window unit. I don't understand what's the most effective way to cool my little studio condo and save money. Please help.

It's worth buying a new one - period! Unless you won't use it much. But the lower the amps the more expensive they are and it's worth every penny (mine is 6.5 amps and 8,000 BTU). Yours could be twice the amperage.

I don't like AC so haven't even installed mine despite 90+ heat. I open windows at night, use a fan or two, close them in the morning, and lower the shades. Works fine. It's what our ancestors did.

Thank you for your reply. I should've explained this in my original post, but I can't open my windows in my unit because 1) I don't have screens, and 2) I'm on the ground floor, and I just don't think it would be safe (I live in D.C.). So, I HAVE to use some kind of fan, and my A/C unit has been on fan only (not cooling) and I also have a free-standing fan as well. I don't understand amps/amperage, so I'm not sure what to do, but I DO agree that I should probably just invest in a new unit. I just wanted to save money starting right now. Also, is it worth it to shut it off during the day? I didn't know if it would take too much energy to cool the place down, but it's not that cool to begin with. Hmmm. I'm answering some of my own questions. I appreciate any and all feedback. You guys are awesome.

If you are gone 8 - 9 hours, sure, shut it off, and tolerate the stifling heat for 5 minutes when you get home. Yes, you will save. A studio condo can cool down pretty fast.
The lower the amps, the lower your electric bill will be by a LOT. You might be able to read them on a little plate on the unit.
It might not pay for itself this year though - it depends totally on how much you use it.
You can cool a studio with 5,000 BTUs but I'd get 7 or 8,000.

It's a good chance that it will not be as effective in hot weather as something brand new (and in your case getting s new system might be the best option. But as for mounting the setups vary. It requires correct support and maitnence steps to be taken. In other words, if your windows frames slanted, put some wood underneath to make it sit straight. Close all the space around that system along with any windows in the room and the door. Properly fasten it if screws are included if not have someone help you install it that way. As for maitnence, clean the filter on a regular basis when crap collects in it (u can use running water) the filter is located by opening up the front panel, but in your case read the manual. Hope I helped.