Free webinar on bookkeeping made me ditch my paid software

Back in March I signed up for a local small business meetup that had a free webinar about bookkeeping basics. I figured it would just be a sales pitch for some expensive software, but the host actually walked us through a simple spreadsheet setup that replaced my $80 a month app. Two months later I caught a duplicate charge that the old system missed, which paid for my gas and lunch ten times over. The real kicker was learning that my side gig was actually losing money on certain jobs once I tracked mileage and materials properly. Has anyone else gone to a free event expecting trash and come home with something that actually changed their numbers?