What's a good way to do live vocal processing?

I want to be able to add a touch of live effects to my vocals while playing guitar. Is there a half-decent thing I can put between the mic and the mixing desk that I can pref control with my foot to add perhaps a bit of reverb/delay/other fx to the mix when I want which won't break the bank. We have a fancy Helicon thing as a band which we've never had much luck with using. I'd prefer something maybe a bit simpler, which isn't fussy about how it's plugged in either (we've had compatibility problems with the Helicon in the past too).

Boss VE-20