Table schema

lower age limit
upper age limit
full week (True or False)
day
overnight (True or False)
accommodation
fee

Here are some initial observations, and an attempt to separate threads of pricing into discrete parts.

Memorial meeting only is free, so no food or accommodations need to be calculated.
Day attenders aren't charged for accommodations, nor are they shown accommodation options. Day rates vary by age range. There are flat-rate discounts ($10) on specific days (1 and 6) for people above 12 who are not staying overnight.
Overnight attenders fall into two groups: full week overnight and specific day overnight.
    Accommodations prices/options are based on age, with the following structure:
        accommodation type
        age range (lower and upper ages inclusive)
        full week price
        daily attender price
Meals costs are only calculated for people attending specific days (not full-week), either overnight or just daytime. There should be one meal charged per day attending. We have two meal costs:
    Age 0-12 $9
    Age 13+  $15

There is a some kind of "tree" of options for people to select (reflected in the calculation logic) that would make fee calculation a bit more linear/maintainable, such as the following possibility:

enter registrant age (used in subsequent select steps and final calculation)
select "Attending Memorial Meeting only?" -
    Yes (true): bypasses all other accommodations and meal choices
    No (false): show "full-week / specific days" option
select "Attending full week?"
    Yes (true): used in price calculation
    No (false): show "select days attending"
select "days attending" (optional based on previous condition)
select "Need overnight accommodations?"
    Yes (true): show accommodations options
    No (false): accommodations are not calculated into registration price
Program selection (e.g. Children's Program, JYM, YAF)
    options in this field are determined by age eligibility, but do not affect registration cost