Just use those same hole-in-the-wall places, and check two or three places beforehand to insure you're getting the market rate.

Are you Canadian? If so, check the current charge for a five-day visa at Luohu for Canadians. With the new 10-year visa, China seems to be charging Canadians about US$100 for a visa no matter the length of the visa. It would not be surprising at all if this is now the cost at Luohu as well.