Is there a cheaper alternative to Spanx?

I’m going to a wedding and have a kind of clingy dress. A friend recommended Spanx as a tummy-control option. But they cost $68! which seems like a lot to pay for underwear. Is there a cheaper alternative? Last time I wore this dress, I cut the legs off of control-top pantyhose and just wore the control-top, but they kept riding up at the edges. I try to avoid wearing pantyhose if possible—too hot and itchy.