I'm not an expert in US prices, but I would suggest speaking to a local business group in the area (if one exists of course) There is usually some commerce group available that may have a good idea or even a legal adviser. That said, these online options usually are the cheapest and from what I have heard about LZ, although not a lot, is that the service is well priced.
Sorry I can't be much more help than that unfortunately.
Can I ask why you want to incorporate, you're just looking at divesting yourself legally or looking for a better tax deal. I mean is it an expense you really need to absorb at this point?