Parts - buy/sell to help fellow members or make $?

Ok- Im relatively new here... so maybe some "veterans" can help shed some light for me.
Im just wondering if we are here to help each other out... or make a buck taking advantage of each other?
I mean, I too like to make addtl cash on parts- but they are leftover parts I do not need, and many I give away to friends who are in GENUINE need of the part. Im not buying items to turn them over at a profit. I sincerely appreciate when a member lists an item I need at an affordable price.

Example: Saw a part listed just last week that I could have really used at a great price ($20) but it sold quickly. Figured I missed a great deal again.
Well low and behold I go to Moparts today and the same very part is being sold by the person who bought it here for $75!!! and just a week later!

Thats just not right. Again- Im all in it for everybody to make a buck but I thought this site was here to help each other out- NOT take advantage of each other.

Done venting- Merry Christmas!