I agree with bonestructure... if you did this lady a favor expecting payment, you should have told her so upfront. Also, remember elderly people don't always realize how much the value of a dollar has changed, so I doubt she intended to insult you. Plus, I can tell you from experience that regardless of how her financial situation looks on the outside, that may really have been all she could afford. One just never knows.
Honestly, it sounds to me like she is lonely and just in need of some human companionship. You changed a filter, some light bulbs, and advised her on furnature placement. You did a good deed and she 'tipped' you. Leave it at that and feel good about what you did for her. That hour and a half may have very well been the highlight of her whole month.
