Wacom are far and away the best - I believe!
The Bamboo is currently their introductory model and about your budget if you shop around,
USB is the usual connection these days.
Any tablet behaves exactly like a pen giving fine enough control to write your signature.
Wacom change the names of their products quite often and I changed to a larger and more expensive tablet mainly because the pen is nicer to hold, and there's room to be more ambitious over the editing or freelancing you may want to do.
The small tablet size is not to be sneered at, it is quite adequate for most (home) users. All the pens have side buttons emulating left and right click and the nylon point is pressure sensitive.
Good software is packed with it an fuss free in use. In fact it can be used as well as the mouse though not at the same time.
If you want to use the mouse then park the pen in its holder, or if it is the pen you want just move the mouse away first and ignore it