Whilst I agree with those sentiments, I do have some sympathy for Morph's situation. Being in a situation with no cash, this is an easy way to raise some funds to start off.
I assume from his post he checked CMs, and priced the stone below those prices, probably as much for a quick sale as for being nice, but can't have everything

Given current prices of other items etc I don't think 12p is too unreasonable, and it is also not a fixed price as I am sure he would accept less if it was the only offer. There will always be people who can't attend raids, or prefer to spend the cash to buy a stone rather than attend a raid.
The fact that you are running raids, and have offered to try and include anyone who needs a stone, means the demand for stones will be low, and therefore the prices are low, already much less than the 25p seen not too long ago.