The Nappyloc tool is $25 and takes a million years (or two weeks to arrive). The sisterlock tool essentially costs a few hundred dollars because you have to take their training classes in order to purchase. A while back I posted how to make your own tool from an altered yarn needle. But since my hair is long enough, I no longer have to alter and can use the yarn needle whole. I find the needles actually caused my hair less tension and breakage than the often bulkier tools. At about $2 each they are totally worth trying.