Snochaser's Construction Co. Builds

[JensR]

I am not familiar with RadioShack's products, but if you mean the simple 3-pin electronic part that regulates the input voltage down to 5V, this is not the ideal solution:
They typically do not cope with the high currents modern servos need and they are very inefficient, as they waste the extra power as heat. A proper BEC would be better - or a strong battery, if the space is sufficient.
If you know of a 2USD part that does not suffer from the disadvantages I mentioned, could you please provide a link, I'd be seriously and honestly interested.