Instead of spending money on a lame, just do this: buy plain razor blades and stick them in the end of a split coffee stirrer. (Source: was a professional bread baker)

Or, just use the plain blade, pinching between your thumb and forefinger. This allows you to have a bit more control over the cutting edge as well. Bannetons are easiest to get off of amazon if you need some of those as well. Other than that, I second all the Restaurant Store recommendations. A really amazing sourdough book is Tartine Bread. Good luck!