They came with the Caa stock set's I bought that come with the buffer tube assembly,spring and weight.I have no idea what weight they are because I didn't need them for an AR,I just tossed em' in the spare parts box just in case anyone needed a replacement.I don't know what a fair price for them would be,hell I just would be happy to get enough to cover shipping cost.I'll look tomorrow and see if I can find out anything about the how heavy the buffer is.