wig advice needed

we want to get a wig for some roleplaying...if you know what i mean. the stranger in a bar thing!  anyway - any recommendations on buying a realistic but inexpensive wig?  looking at chin length bob styles.  also, do most wig stores cut the wig to your liking?  like if we found a longer bob, would they cut it shorter and angle it ?  what can we expect to pay?  any advice would be appreciated!!