Unlocking iPhone 6 with imei

[sginpa21]

So my wife and I want to each get an iPhone 6. We have metro pcs as our service now. I found one at Walmart for a good deal but offered through their service of Straighttalk. I have read that you can unlock the phone by using an imei service. The question I have is if I do buy that phone can I unlock it without using the straighttalk service at all?

 

[rgd1101]

MERGED QUESTION
Question from sginpa21 : "Unlocking iPhone 6"

So my wife and I want to each get an iPhone 6. We have metro pcs as our service now. I found one at Walmart for a good deal but offered through their service of Straighttalk. I have read that you can unlock the phone by using an imei service. The question I have is if I do buy that phone can I unlock it without using the straighttalk service at all.