Like he said. It's what your willing to spend.
For squeals, I'd go with the MXR Wylde Overdrive, or the cheaper Boss SD-1.
YOu can get single pedal octavers as well. YOu could get a cheap boss, or and expensive electro-harmonix one.
Or if budget is a problem, look into a digitech rp-80 multi-effect. Not the best, but cheap.
I'd personally go single pedals.
For life is quite absurd and death's the final word, You must always face the curtain with a bow
Forget about your sin - give the audience a grin
Enjoy it - it's your last chance anyhow.METOOB