I bought a htc mobile last year from Chicago county which was sold with AT&T Mobile service exclusively,but now I want to change my network operator because there has been lot of problems regarding calls and network problems in the past few months but since the phone is made to be used with AT&T, I am unable to change my network service provider. I got to hear about cheap unlocked phones so I just wanted your suggestion to whether go for these cheap unlocked phones and the best places to buy cheap unlocked phones.