Hi Hype, welcome...
To answer your questions, remember this is based on what you tell us and not what is nessesary there....
The oil leak, it could be as simple as a sump gasget or it could leak out of your crank pully seal, the latter one is a bit harder to fix only because of the time it takes, it could even come from somewhere else, my advice is get this fixed before you buy it because it might just turn out worse than you thaught it would be.
The smoking in the mornings, in my opinion it is the oil seals in the turbo, the "seals actually copperish" stop oil from coming into your compression and exhaust housing, normally when they start to go it lets oil thrue because it is cold and slightly warn, then it gets hot and seals properly.
It could be rings aswell but normally, you can see that in driving, that white smoke will always be there, first a little then it gets worse, you could test it by compression test, take the reading, then add a bit of...wait....maybe you know that already...?
It could even be your valve stem seals, again you will see it in driving, when car is warm and say you in 3rd, take it up to about say 4500 rpm or so then leave it in gear and leave the petrol, it will then smoke as you slow down...because the vacume is sucking oil thrue the VSS.
My guess is the turbo oil seals, I might be wrong.
As for the maintenance, normal services you can do by yourself, the oil and parts depending on where you buy and what you buy will work out R500 roughfly.
If things start to brake...whell that you can't budget on....the point is make sure evrything is sorted and the look after it, still it might brake down but not as bad as when you did not look after it.
Something you need to deal with is that you will have stuff to fix in the beginning, save some money, do it right and you will go strong for another good set of km's.
Whatch out...there is alot of bullshitters out there, hence, do what you can yourself or at least be involved to try and make sure it is done right.
PS...if you buy...goodluck with the camry
