The most sturdy swing sets are the wooden sets.
I checked on the Austin Craigslist, there were a few listed under "household items".. You could also check under "general"...Make them a deal, especially if they have been listed for a while. Maybe you could get some relatives, friends or neighbors to help you guys take down and then move a swing set and then rebuild it.. Host a huge cook out as a thank you.
To make money for special items, we have always done garage sales.. We get rid on everything that we have not used in over a year.Furniture, rugs, clothing, toys, whatever..... It cleans out the house and gives us cash for the special items we normally could not afford.