(Not sure if my linking will work, but if not just copy and paste).
At one point in the sermon he told about how people had generously given of their resources to enable some teens to go to camp - and how this time for them would be spiritually enriching and potentially life-changing. He said that during their time there half of the group had made life-changing decisions and been won to Christ. This was all in the context of talking about generosity and our hearts being in the right place.
At that point in the sermon I suddenly realized that happiness can be bought after all. You see, it made me happy to hear of these lives that were changed. I rejoiced in the expansion of God's kingdom. I had my own share of joy over these whose hearts now join with my own in worship of our Lord. And while this is all a result of God's work in their lives, God had given the opportunity for us to put our resources into this work and be partners together with Him in the task of building His kingdom. So, if we put our resources into HIS work, and the results of HIS work make us happy, then, I daresay, happiness CAN be bought.
Just put your money in the right place.
Because, if I go out and blow $100 on some frivolous items that bring me a smile and that I can enjoy (which of course isn't wrong, and I have to say that clearly here because I have a great distaste for legalism), or if I put that same $100 into eternal riches - which one will buy me the most enduring happiness? The stuff will eventually rot, break, decay or collect dust. Eternal riches - lives changed, hope restored, the lost redeemed, fruit being borne of difficulty - all these will not rot, decay or break - because when God starts a work, He completes it (need I remind you that an oft-quoted favourite verse is actually related to finances? Philippians 1:6 'He who began a good work in you will be faithful to complete it...' is part of Paul's thank-you note to the Philippians who supported him in his missionary work...but I digress).
So, go out and be generous and buy yourself some happiness - of the sort that lasts.