---The psychological evaluation is to try to be sure that you fully understand what you are doing, are acting freely, and have reasonable motivations. Just be honest. And since some donors suffer depression after surgery, any past problems with depression would have to be prudently taken into account.
--- If you were delusional (e.g.: "the little green men from the flying saucer told me to donate"), or had unreasonable expectations (e.g. "I am a horrible person and have ruined my life, but if I donate a kidney everything will be wonderful and all my problems will go away and everybody will love me") you would have trouble being approved.
--- You don't have to be in PERFECT health, but must be healthy enough to safely give a usuable kidney without endangering your own future health. So your health must be pretty good
--- They will want to know whether you have family support in your decision.
--- With regard to income, you have to keep in mind that you may lose wages during recovery (and some donors are unable to work for a longer time if complications occur), and that some donors have reported difficulty in getting/keeping reasonably priced health insurance after donation.
--- Doesn't SEEM to make much difference left or right.
--- Recipients usually have failure in both kidneys (probably would not need a transpant if they still had one good kidney). Left or right makes not much difference. Often the donated kidney is placed in the abdomen, not where the kidneys are.
Hope some of this info helps. Keep asking questions and getting well informed.
best wishes,
FR. Pat