search all these keywords in the 精华区, you will get answer
if you do not need CID, you can use rynga.com, nonoh.net, voipdiscount.com, voipbusterpro.com, all these are BETAMAX company with cheaper price.
if you need CID when you call out, use sipgate.com, onesuite.com, callwithus.com, localphone.com.
if you have needs to transfer your PSTN number to, use onesuite.com, localphone.com and callcentric.com.