I struggle with this as well. I never like to feel like I "owe" someone. Many times friends will pick up the tab - and many times I ask to pay the tip - them treating me to something nice is wonderful...if they argue - I tell them to let me do it for me
Other times when someone wants to go out.. I know I do not have enough $ I say so upfront. I usually pass on going...and let them know I'd like to do something some other time.
I have learned to be incredibly independent and have real issues asking for help - makes me sick to my stomach. And I cannot hardly wait to pay back them back.
If I ever had to ask for help from my family (I never ever abused this)....it was awful. You were shamed. I'd rather chew off my arm then ask them for $ help.
If I do have extra - I always like to treat those that have been good to me.