Its good to see that Wilt doesnt read any of the previous posts
I did read them all first! People are telling him to read histograms, people are telling him to calibrate monitors, people are telling him to buy meters (but his budget does not permit that)
The problem with histograms is that unless you KNOW where the brightness of the object is, you do not know where to expect that to peak in the histogram. If you have a gray card, you can shoot it and target its position at the midpoint, but if you have a gray card you can simply shoot what the Partial meter or Spot meter reading is from the card, and not bother with the in camera histogram. When your target is 18% gray with no highlights, the ETTR is a useless concept.
Calibrating monitors can't be done unless you have established levels of brightness in the exposure, a reference standard. That is why software provides established RGB values that a monitor calibration unit can read, so that the monitor is then adjusted to recreate that known reference! If you have no software generated reference standard, then you need to use a reference standard like a gray card or a Macbeth card (which is probably not in the budget either, I would guess).