Going rate is a tough one.
If I am playing a pub, I would expect £30-50 (all prices as an individual, not a band) and that it would be no-stress and material that I (hopefully) like to play anyway. I don't do those gigs anymore, though. As a family man giving up a Saturday night for £30 is not OK.
If I am playing a social club, it's more £60-80 (max). But those are horrible.
If it's a wedding/corporate event - £150 Minimum up to £250.
If it's a community musical, sometimes it's like £200 for a 4 night run and a rehearsal - I love doing these, though - proper reading gigs.
I did one dep for a major national musical tour. All considered, it's lots of travel and pressure for less than average money. Glad I did it just for the experience, though.
Anyway - basically its all down to what you can afford/demand and where you are in your life.
At one point, I loved doing those £30 gigs. Now I won't do it because I don't have to.
Teaching pays the bills for me though! I feel blessed.
J