You have to pay if it's a valid ticket. Otherwise they will come after you with debt collector and possibly affect your credit score.
However, you can appeal. Please do not appeal via internet or mail. You will never win. The only way to win is to appeal in person.
When you got the ticket, your appeal process should start. You should read the ticket very very carefully. Are all information accurate? Did they put down the right address, right violation code (code needs to match the sign) etc. etc. Take pictures and print them in color!
For NY licensed cars, we are mostly SOL as they just scan the registration and all information goes from DMV to the ticket against you (where is our 6th amendment right against self incrimination?)
For out of state licensed cars, the meter maids actually can make mistakes quite often. They often write down the wrong car type, color, no expiration date, etc. etc. Fight the ticket if you can, they don't let you plea with a discount anymore so you have nothing to lose.
