Firstly, SOCOM, sorry about your child. As a father of 4, I can sympathize.
SOCOM, what you offered up as an excuse for your actions was touching, but why did you not contact the original purchaser and offer it up to him at the original agreed upon price ?
I had once made an offer on a rifle for sale and the offer was accepted. The seller then emailed me that he was in a quandary as someone offered him more after we made a deal.
All I told him was to do what he thought was right, and if that meant going for more money after our "handshake", there was really nothing I could do about it. Needless to say, I got the rifle at the agreed upon price and would not only gladly do business with him again, I can confidently recommend him to others.
You should have done the right thing too.
Secondly, since when does a child "want" OR "need" a Dillon Press with all the bells, buzzers, and whistles?