Here is a pleasant surprise: the Internet Archive is placing the 1930 U.S. Census online and is making it available at no charge. This is a "work in progress;" but, the census records from many states are available now, and the remaining states will be added in the near future.
The records are offered in exactly the same format as the microfilms created by the U.S. Government. In fact, the online images appear to be copies of the microfilms. The images are being offered "as is." That is, there is no index available, only the images. If you already know where your ancestor lived and (hopefully) the enumeration district, you can view the images one at a time until you find the information you seek.
You can find enumeration districts on FamilySearch at http://www.familysearch.org/Eng/Library/fhlcatalog/supermainframeset.asp?display=subjectdetails&subject=870702&subject_disp=Census+districts+-+United+States&columns=*,0,0. Once you know the enumeration district, return to the Internet Archive at http://www.archive.org/details/1930_census to conduct your search.
If your ancestors lived in a small town, you can probably find them without determining an enumeration district in advance. However, for those who resided in cities, the enumeration district is a valuable piece of information that allows you to zoom in on the correct neighborhood quickly although you will still need to look at a lot of images to find what you seek.
While it is nice to see a free version of the census available, I doubt if this will have much impact on the commercial companies that also offer census images online for a fee. The commercial companies have indexed most of their records, and finding someone in an index first is much, much easier than manually looking at hundreds of images in search of the right family.
While I appreciate the free, unindexed images, I'll still gladly pay a few dollars a month to have an index available. I suspect most others will do the same, especially after trying to find someone in the free records.
Of course, now is an excellent time for your genealogy society or historical society to index the records for your area and place your own index online, with each entry pointing to an original record on the Internet Archive.
To find the 1930 U.S. Census records on the Internet Archive, start at: http://www.archive.org/details/1930_census to conduct your search.