As a little girl, my dad once took me on an impromptu field trip to the fire station. We were waiting for the car to be fixed, the fire house was right next door, and we had some time to kill. The firemen were more than happy to show us around and in addition to the educational benefits, it provided me with some fond memories of time spent with my dad.
There are lots of free field trips that you can take with your children, or organize with your homeschooling support group. Bakeries, police and fire stations, factories, gardens, museums, grain mills. farms, etc. all make great field trips. Our local grocery store (Meijer), bookstore (Barnes and Noble), and pizzeria (Hungry Howies), all offer free field trips. Of course, my favorite field trip of all time is Krispy Kreme!
For a religious field trip, check out shrines, churches, cemeteries, convents, seminaries, etc. I personally love visiting old churches and several offer free tours. We once went on a "stain glass tour" of a local cathedral. It was quite educational.
Or bring the field trip to your house by inviting speakers such as a minister, scientist, politician, etc. One of our best homeschooling experiences was when an entomologist (an insect specialist) gave a presentation about bugs to our homeschool group. The kids loved it!