What does 'penny for the guy' mean?

"Penny for the Guy" is the idea that children in Britain collect money to buy fireworks for Guy Fawkes night. Guy Fawkes was a member of the conspiracy to blow up the Houses of Parliament. It is one of those strange British quirks that every year we celebrate the occasion by making a dummy of him and children collect money to buy fireworks and then proceed to set light to the dummy and let off the fireworks on November the 5th.

To mark Guy Fawkes Day, children traditionally carry effigies of Fawkes -- known affectionately as "Guys" -- begging for "a penny for Guy," which they use to buy fireworks. The effigies are later burned.

https://www.quora.com/What-does-it-mean-to-penny-someones-car

Lately, however, the custom of begging for a "penny for the Guy" has almost completely disappeared

https://en.wikipedia.org/wiki/Guy_Fawkes_Night

I remember very well, with my brothers, making a guy from old clothes stuffed with leaves etc and pushing it around the streets..'penny for the guy mister'. Then it was put on top of the bonfire in the garden and burnt. Fire works put in his pockets! Now the 5th of November has been taken over by the celebration of Hallowen. Great shame!