I've seen a few posts where people have used the soapy water from the wash as clay lube. Even some where they use fairy liquid instead of shampoo, (don't tell anyone I used the F word) which sort of makes sense if you're stripping right back to naked paint, but I'd be tempted to fill a new soapy wash bucket (with shampoo not FL), and use that.
Either way, should be cheaper than QD or a dedicated clay lube like DJ Born Slippy - though it is relatively cheap, so it's not a big deal if you clay about once a year like me.