All you really have that's free is someone's yard, I would look at public parks, depending on the area some are quite inexpensive. In st peters there's a gazebo that rents I believe for under 200, theres also another in lake st Louis. Also look In like carondolet park, forest park, etc. Where is your reception?
I got married at St. Ferdinand Park In Florissant, MO. It came part of a package with the officiant for $50. I got married in the gazebo right off the lake and it was gorgeous. The officiant was great and handled the park rental. I'm not sure how much the rental would have been if I had done it myself, however you can always contact the Florissant Parks Dept. to see. I have more pics and would be willing to share and give you the officiants info if you are interested.
Unless your guest count is less than 20 people, you will have to rent the space to hold the ceremony. The Music Stand is that much because it includes chairs/benches. No park anywhere will allow you to use the park for free, even if you do not have chairs. This guarantees YOU have the spot to hold the event.
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