The quantity of menus at a wedding is influenced by numerous factors.  And while budget can be the main driving force behind a decision as it’s important to work within what is affordable (or time if you’re making them yourselves) it’s wise to think about what quantity of menus would suit the table and catering arrangements of your wedding or event.
Menu Tent
If yours is one of those rare and very lucky weddings where your guests are able to choose some or all of their wedding food on the day of the wedding I would recommend either one each or at worst one between two.  If they’re choosing each course it is essentially a restaurant style situation and there people are used to having their own menu.  If it’s just a course that is being chosen the amount of time each guest will need to look at a menu is much less and fewer menus will be necessary.
Como Booklet Menu

 

Where your guests have pre chosen or there is a set menu the idea of the menu is to remind people what they have chosen or inform them about what they’re about to eat.  The minimum I would recommend is one per table where your guests are on round tables.  You can probably get away with this for up to 10 or 12 people at a push.  Though 1 between 4 would be good, you can think of this as essentially one shared between four couples while one between 6 is not too bad.  It’s easier to get away with fewer menus on round tables though as everyone will hear if someone asks where the menu is and as it goes along a table it will end up back at the beginning.
Where tables are long and thin I would suggest not going below 1 menu between 8 people but again 1 between 4 or 6 would be much better.
Como Menu Sheet

The only other consideration is that some menus can look really good and rather than a functional item reminding guests what they’re eating but it can be an integral part of how each place setting or table is presented.  It can look great to have one presented on each place setting and if you are having one per guest, why not do away with the place names and personalise the menu.  While menu booklets or tents can be an attractive part of the overall table layout. 

Modeno Menu Tent