I don't know how to rate its potency since it's the only strain I've tried, but I did get euphoric and muscle-relaxing effects. However, these effects were not immediate. I drank it for about 4 days straight (2.5 cups/day) and only felt a little tired, but over time I built up a "reverse tolerance" to it and noticed that the more I drank it, the stronger it would come on. I bought the Fijian Waka Kava Powder and used a stocking I had at home to strain it. I used 1 heaping tablespoon of powder to 1 cup of warm (75-80) water.
As for the price, it seems consistent with a couple of other sites I've visited. Kavabyrex, for example, has their prices set at $30/pound.
I'll probably go through a different site the next time I buy, but overall I'm happy with my purchase; no regrets.
https://www.amazon.com/dp/B00A80163M/ref=cm_sw_r_cp_apa_glt_fabc_BPZMRW1M8ZFAFXT22ZVS?_encoding=UTF8&psc=1 This is the first one I ever tried. It's been around for at least 6 years