>>10102223
I'll be honest it depends on the guests, how far, what friends are going, and the prizes...
My max is 60 dollars, because you already have to pay so much for a convention ticket, usually. Guests matter since depending on who goes, means the con will also have things in the dealers room, and they usually contribute a prize.
I limit myself to one a year though, because its pretty pricey and the food/decorations are always sad.