I like iFlora because it's got a very wide range of bacteria, including some that are naturally found in the colon (where the enema will be going). Not sure what you feel to be expensive, but iFlora runs about $21 or so for a bottle of 60 caps on iHerb dot com. If that's too much for you I would say anything from Now Foods that includes both lacto and bifidum should be good.
Believe it or not enemas are actually refreshing once you get used to them. I really wish I'd been doing them years ago; I probably never would have gotten sick in the first place.
Going to try an enema with borax tonight for the first time. I feel like I've finally got the yeast on the run after drinking 1/8 tsp of borax in 1l of water for the past couple of days. Been passing yeast in my bowel movements regularly. We'll see how it goes.