Go to S.S Sports (Queensway shopping center). #02-30, prices are reasonable, $16 for a BG66, with further discounts, and they use Yonex stringing machines. Good workmanship and quite fast (30minutes), walk around look at other rackets, or meals at Mac and they will call you when done.
Say hi to Ashraf at newlink sports for me. He can string pretty well on 2nd floor in Queensway. If you are in Yishun, let me know. Can give you superhigh tension is you want it.