Surface wife purse with damp cloth.
(Saddle Soap, about $7 at a local Ralphs, which means if you aren't lazy like me you can probably find it cheaper)Use soft damp cloth (or brush) and froth Saddle soap on it before applying it to leather.
Rub and buff.
Result after Cleaning:
Oil the purse by rubbing oil to the leather with a clean soft cloth or brush. Normally "mink oil" is recommended for this purpose, but I've heard of people using even olive oil without any problems. If your purse is very expensive, I would go to the pet store and ask for mink oil. I have already tested out Johnson's Johnson's baby oil on a purse in this post so I am not at all worried about using it on my new purse!
P.S. I did not edit these photos for light or color, only resizing and cropping so pictures are with flash in the afternoon light and should be accurate.