Many local libraries have internet access to proprietary databases as you have mentioned. But it *may* be possible to avoid a trip to the library of your choice. Check to see if the databases are available to you remotely when you log on with your library card. This practice differs from library to library across the country.
By the way, for those folks in California, many libraries throughout the state allow reciprocity with other California libraries in giving library cards to residents. (I live in Contra Costa county but can get cards from San Francisco Public, Berkeley Public and a number of other library systems if I apply in person with a California id.)
Quick Answer: Creativity and flexibility may expand your choices when searching for free databases.