This is a sample only.  The price you charge for the product and tax will most likely be different. 

20% Formula for Jar Fundraiser: 

100 jars sold for $14.00 each to include shipping and tax.  Total collected:  $1400.00.
Tax rate is 5.9%

20% of compensable sales (actual retail cost - not the total charged for the fundraiser) to organization - $259.00 (100 jars x 12.95 = 1295.00 and 20% = 259.00)
25% hostess credit used to order jars - $259.00 ( 80 jars [100 - 20 used for Hostess Credit] x 12.95 = 1036.00 and 25% = 259.00)

Show Summary and Order Forms:
Order 8 per order form.

For example:  Amount collected:  1400.00 in sales from organization. (100 jars x 14.00 each = 1400.00)

Show Summary: 8 jars ordered per order form but only 80 actually written up as guest orders @ $12.95 each.  
80% (or in this case - 80 jars) goes on comp. sales - 1036.00.  ( 80 jars x 12.95 each = 1036.00) 
20% (or in this case - 20 jars) goes under the hostess credit which is 259.00 ($12.95 x 20 jars = $259.00).  
Total due on entire order to PL:  $1153.18.  (113.42 per order form with 8 jars on it x 10 order forms = 1134.20Hostess Total Due:  (Nothing due for hostess credit since 20 jars = 259.00 and this was the total hostess credit we received free for the 1036.00 compensable sales for 80 jars.  However, tax and shipping on the 20 jars is 3.50[shipping] + 15.49 [tax on free items and shipping] = 18.98 total due for hostess credit side)  THUS, total due to PL is 1153.18 (1134.20 + 18.98)
You collected 1400.00  and you will send PL 1153.18 and give the organization $259 (20%). {1153.18 + 259.00 = $1412.18 total.} 
 Your out of pocket expense (before profit check) is $12.18.  
Actual profit from this fundraiser for you:  $246.82 (259.00 - 12.18 = 246.82)
You gave the organization $259.00 (25% of compensable sales and what your profit check is if you don't bonus).

Did you get that?
You collected a total of 1400.00 from the sale of 100 jars + you will receive a profit check of 259.00
(1400 + 259 = 1659.00 Total)
You sent PL 1153.18 and gave the organization 259.00 (1153.18 + 259.00 = 1412.18)
Total collected: 1659.00
Total spent:      -1412.18 
Total profit:         246.82

This is just one way to figure up the final show summary.  You can order all the products on guest orders and use the hostess credit to order extra products for yourself if you prefer.  But doing it this way, you won't realize any cash profit - your profit check will go to them.  However, you would receive $323.75 in free products from the hostess credit that way. 

How you write up the fundraiser show is up to you.  The Tally Sheets really help in that respect so you can decide what you'll need to charge to cover your tax and shipping.