Is if bribery if it works?

I once had a friend, a fellow special educator, tell me, If you bribe your kids and it works, it's not called bribery, it's called "effective parenting". But if it doesn't work? Then it's totally bribery!"

Yesterday Angela and I had a bunch of errands to run, all of which revolved around Axel. We also stopped at Target and bought a few pairs of underwear, socks and pajamas for him. He'll be handed over to us in his birthday suit, so we have to bring clothes along. 

Angela liked picking out boy pajamas and the underwear. ( I think she was fascinated with the fact she was shopping for boys underwear. ROFL)  She REALLY likes shopping in the boys clothing section in general because they have lots of stripes there, and the girls section has very few! Who knew? LOL Anyway, we ended up having a small issue with one princess teenager getting a little jealous over all this shopping for Axel that was going on. I didn't say anything to her to feed into the poor me moment she was having, but I did wander over to the Vikings jerseys and ask her, "Weren't you asking Dean about getting a football jersey this year? Since you've done such a great job helping me pick out this stuff for Axel, and reminding me that I need to get my office supplies too, you can pick out which Jersey it is you wanted to get."

Oh, that was one very exited young lady who got to pick out her Brett Farve jersey! 

I have NO idea if this was the right thing to do or not. I wanted to praise her for helping out with something that had to do with the new brother who's coming very soon, who although she can't yet see him, had taken my attention this entire morning. She never complained, but I could see that it was getting to  her. I wanted to catch her being good before she turned on me! So I did what any good mother would do and I bought her love.  Does that count as a bribe, or "effective parenting"? Or neither? So, which attitude did I encourage her to display in the future? The one that is willing to be  helpful (as long as there is something in it for her!) or the one that is crabby she we are shopping for someone else?