I think Wal Mart sometimes has them. I bought one online when I could not find one. People don't use them like they use to, it seems. You might do a search for enemas kits and see if you pull up a name of a local drugstore.
The Walmarts here in Arkansas carry enema bags for about $5.00. They are good quality and last for several years. One Walmart had them in the laxative section, another one (a Division One store) had them with the health supplies like latex gloves, eyedroppers, and similar items. Don't be embarrassed to ask; I had to at the little store.