Buying and donating a bicycle in Nakhon Phanom

I'm due in Nakhon Phaom in a couple of weeks time (my 4th trip) and have decided to buy a second hand bicycle (hopefully) rather than settle for one of the ancient offerings from LA Cycles or using a communal one from my Hotel.

Assuming I find one worth buying, I am hoping to be able to sell it at the end of my weeks stay but accept that this may be difficult.

My second choice was to donate it to a worthy cause or recipient.

Can anyone advise on any charitable organizations that may accept a bicycle?

Or better still - does any one living in Nakhon Phanom have a half decent bike they would like to rent for a week?